Anti-human epidermal growth factor receptor-2 (HER2) immunization can be elicited by vaccination with DNA encoding the extra- or intra-cellular domain (ECD or ICD) of HER2, naked or encap-sulated in viral vectors. HER...Anti-human epidermal growth factor receptor-2 (HER2) immunization can be elicited by vaccination with DNA encoding the extra- or intra-cellular domain (ECD or ICD) of HER2, naked or encap-sulated in viral vectors. HER2-peptides derived from ECD or ICD of HER2, and HER2-pulsed dendritic cells (DCs) or engineered DCs expressing HER2, respectively. We performed a computer- based literature search which includes but is not limited to the following keywords: breast cancer, immunotherapy, HER2-peptide vaccine, HER2-DNA vaccine, HER-DC vaccine, HER2 vaccine, and HER2/neu, in PubMed, Medline, EMBO and Google Scholar;data from recently reported clinical trials were also included. Drawing upon this synthesis of literature, this work summarizes the de-velopment and current trend in experimental and clinical investigations in HER2-positive breast cancer using HER2-specific vaccine and immunotherapy, focusing especially on: (i) DNA-;(ii) peptide-;and (iii) DC-based vaccines. It addresses interventions that have been applied to overcome immunotolerance thereby to improve treatment outcomes. These include blocking the inhibitory cytotoxic T lymphocyte-associated protein-4 (CTLA-4), which is expressed at high levels by regulatory T (Treg) cells, or complete Treg depletion to improve T-cell activation. Moreover, modulatory interventions can provide further improvement in the efficacy of HER2-specific vaccine. The interventions include the use of immunogenic adjuvants such as cytokines interleukin-12 (IL-12), tumor necrosis factor (TNF)-α and granulocyte-macrophage colony-stimulating factor (GM-CSF), the use of Toll-like receptor (TLR) ligands and tetanus toxin’s universal epitopes such as the CD4+ help T (Th)-epitope P30, and the use of either chimeric or heterogenous xenogeneic HER2. Combining active HER2-vaccination with adoptive trastuzumab antibody immunotherapy is likely to increase the effectiveness of each approach alone. The development of effective HER2-vaccines for breast cancer remains a critical challenge. Though these novel interventions seem promising, further investigation is still needed since the results are preliminary. Furthermore, the review discusses the challenges and future perspectives in HER2-vaccine research and development.展开更多
Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor s...Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor suppressor genes. Central to all these therapies is the development of efficient vectors for gene therapy. By far, adenovirus （AdV）-mediated gene therapy is one of the most promising approaches, as has confirmed by studies relating to animal tumor models and clinical trials. Dendritic cells （DCs） are highly efficient, specialized antigen-presenting cells, and DC- based tumor vaccines are regarded as having much potential in cancer immunotherapy. Vaccination with DCs pulsed with tumor peptides, lysates, or RNA, or loaded with apoptotic/necrotic tumor cells, or engineered to express certain cytokines or chemokines could induce significant antitumor cytotoxic T lymphocyte （CTL） responses and antitumor immunity. Although both AdV-mediated gene therapy and DC vaccine can both stimulate antitumor immune responses, their therapeutic efficiency has been limited to generation of prophylactic antitumor immunity against re-challenge with the parental tumor cells or to growth inhibition of small tumors. However, this approach has been unsuccessful in combating well-established tumors in animal models. Therefore, a major strategic goal of current cancer immunotherapy has become the development of novel therapeutic strategies that can combat well-established tumors, thus resembling real clinical practice since a good proportion of cancer patients generally present with significant disease. In this paper, we review the recent progress in AdV-mediated cancer gene therapy and DC-based cancer vaccines, and discuss combined immunotherapy including gene therapy and DC vaccines. We underscore the fact that combined therapy may have some advantages in combating well-established tumors vis-a-vis either modality administered as a monotherapy.展开更多
Human immunodeficiency virus type-1 (HIV-1) chronic infection causes millions of deaths each year. We previously developed a novel HIV-1 Gag-spe cific exosome (EXO)-targeted T cell-based vaccine (Gag-Texo) using ConAs...Human immunodeficiency virus type-1 (HIV-1) chronic infection causes millions of deaths each year. We previously developed a novel HIV-1 Gag-spe cific exosome (EXO)-targeted T cell-based vaccine (Gag-Texo) using ConAstimulated polyclonal CD8+T (ConA-T) cells armed with Gag-specific dendritic cell (DC)-released EXOs, and showed that Gag-Texo stimulated more efficient cytotoxic T lymphocyte (CTL) responses than DCs. Tat HIV-1 early regulatory protein possesses immunomodulatory and adjuvant properties. To enhance Gag-Texo immunogenicity, we generated Tat-engineered OVA/Tat Texo and Gag/Tat-Texo vaccines using ConA-T cells armed with EXOs release by DCs infected with recombinant OVA/Tat- and Gag/Tat-expressing adenoviruses (AdVOVA/Tat and AdVGag/Tat). We then assessed vaccination-stimulated CTL responses in naive mice, and therapeutic immunity in transgenic HLA-A2 mice bearing Gag/HLA-A2-expressing BL6-10OVA/A2 melanoma lung metastases. We demonstrate that the OVA/Tat-Texo vaccine enhances functional OVA-specific CTL responses, compared to the OVA-Texo vaccine, and broadens CTL responses recognizing the cryptic OVA epitope in C57BL/6 mice. Furthermore, we determine that the Gag/Tat-Texo not only stimulates more efficient CTL responses than Gag-Texo, but also induces enhanced therapeutic immunity. We show that, 30% of Gag/Tat-Texo-immunized mice are free of tumor lung-metastases, compared to all Gag-Texo-immunized mice displaying lung-metastasis. In addition, the average number of tumor lung metastases colonies (32/lung) in the Gag/Tat-Texo-immunized mice was also significantly lower than that (78/lung) observed in Gag-Texo-immunized mice. Taken together, this indicates that HIV-1 Gag/Tat-Texo capable of stimulating enhanced Gag-specific CTL responses and therapeutic immunity may become a new immunotherapeutic vaccine candidate for controlling virus in HIV-1 patients.展开更多
BACKGROUND: We assessed whether the paediatric-appropriate facilities were available at Emergency Departments(ED) in community hospitals in a Canadian province.METHODS: We conducted a cross-sectional survey of EDs in ...BACKGROUND: We assessed whether the paediatric-appropriate facilities were available at Emergency Departments(ED) in community hospitals in a Canadian province.METHODS: We conducted a cross-sectional survey of EDs in community hospitals in Ontario, Canada that had inpatient paediatric facilities and a neonatal intensive care unit. Key informants were ED chiefs, clinical educators, or managers. The survey included questions about paediatric facilities related to environment, triage, training, and staff in EDs.RESULTS: Of 52 hospitals, 69%(n=36) responded to our survey. Of them, 14% EDs(n=5) had some separated spaces available for paediatric patients. About 53%(n=19) of EDs lacked children activities, e.g., toys. Only 11%(n=4) EDs were using paediatric triage scales and 42%(n=15) had a designated paediatric resuscitation bay. Only half of the ED(n=18) required from their staff to update paediatric life support training. Only 31%(n=11) had a designated liaison paediatrician for the ED. Paediatric social worker was present in only 8%(n=3) of EDs in community hospitals.CONCLUSION: Most of the Ontario community hospital EDs included in this survey had inadequate facilities for paediatric patients such as specific waiting and treatment areas.展开更多
CD8+ cytotoxic T lymphocyte (CTL) exhaustion is one of the major obstacles for the effectiveness of virus control in chronic infectious diseases. We previously generated novel ovalbumin (OVA)-specific 41BBL-expressing...CD8+ cytotoxic T lymphocyte (CTL) exhaustion is one of the major obstacles for the effectiveness of virus control in chronic infectious diseases. We previously generated novel ovalbumin (OVA)-specific 41BBL-expressing OVA-TEXO and human immunodeficiency virus (HIV-1) Gag-specific Gag-TEXO vaccines, inducing therapeutic immunity in wild-type C57BL/6 (B6) mice, and converting CTL exhaustion in recombinant OVA-specific adenovirus AdVOVA-infected B6 (AdVOVA-B6) mice with chronic infection. IL-21 cytokine plays an important role in controlling chronic infections. Therefore, in this study, we constructed recombinant transgene IL-21-expressing AdVIL-21, and generated IL-21-expressing OVA-TEXO/IL-21 and Gag-TEXO/IL21 vaccines, or control vaccines (OVA-TEXO/Null and Gag-TEXO/Null) by infecting OVA-TEXO and Gag-TEXO cells with AdVIL-21 or the control AdVNull, lacking transgene, and assessed their effects in B6 or AdVOVA-B6 mice. We demonstrate that both OVA-TEXO/IL-21 and control OVA-TEXO/Null vaccines are capable of converting CTL exhaustion in chronic infection. However, the OVA-TEXO/IL-21 vaccine more efficiently rescues exhausted CTLs by increasing stronger CTL proliferation and effector cytokine IFN-γ expression than the control OVA-TEXO/Null vaccine in AdVOVA-B6 mice with chronic infection, though both vaccines stimulated comparable OVA-specific CTL responses and protective immunity against OVA-expressing BL6-10OVA melanoma lung metastasis in wild-type B6 mice. In vivo, the OVA-TEXO/IL-21-stimulated CTLs more efficiently up-regulate phosphorylation of mTORC1-controlled EIF4E and expression of mTORC1- regulated T-bet molecule than the control OVA-TEXO/Null-stimulated ones. Importantly, the Gag-TEXO/IL21 vaccine induces stronger Gag-specific therapeutic immunity against established Gag-expressing BL6-10Gag melanoma lung metastases than the control Gag-TEXO/Null vaccine in chronic infection. Therefore, this study should have a strong impact on developing new therapeutic vaccines for patients with chronic infections.展开更多
The occurrence of multiple primary cancers is rare;it can be missed as a disease progression. The etiology remains controversial. We report a case of a 55-year-old female with metastatic renal cell carcinoma treated w...The occurrence of multiple primary cancers is rare;it can be missed as a disease progression. The etiology remains controversial. We report a case of a 55-year-old female with metastatic renal cell carcinoma treated with sutent followed by left sided nephrectomy. Follow-up CT showed increase in the size of the right axillary lymph nodes which was proven after biopsy to be metastatic adenocarcinoma of the breast. Any suspicious disease progression in a single site not compatible with disease history should be biopsied for confirmation. The relationship between renal cell carcinoma and breast cancer is still unclear, and more case reports are required to determine this relationship.展开更多
Introduction: Leukemoid reactions in cancer are rare and associated with a poor prognosis. The mechanism driving paraneoplastic leukemoid reactions appears to be gain-of-function granulocyte-colony stimulating factor ...Introduction: Leukemoid reactions in cancer are rare and associated with a poor prognosis. The mechanism driving paraneoplastic leukemoid reactions appears to be gain-of-function granulocyte-colony stimulating factor (G-CSF) secretion by tumour cells. Case Presentation: A 57-year-old male smoker presented with a one-year history of painless frank hematuria and three kilograms weight loss. Cystoscopy revealed a high-grade urothelial carcinoma with sarcomatoid differentiation. The patient was treated by radical cystoprostatectomy, bilateral pelvic lymph node dissection and formation of an ileal conduit. In the absence of bone marrow infiltrations, recurrence of the urothelial carcinoma three months later was associated with a paraneoplastic leukemoid reaction with a white blood cell count peaking at 82.62 × 109/l. Unfortunately, his condition continued to deteriorate and he died shortly thereafter. Conclusion: Monitoring of white blood cell counts in paraneoplastic leukemoid reactions can be a useful indicator of response of the malignancy to chemotherapy or radiotherapy and an indication of relapse after treatment. Paraneoplastic leukemoid reactions are caused by G-CSF secretion by tumour cells and are associated with a poor prognosis. Whether G-CSF signaling plays a role in the aggressive nature of these cancers is currently unknown.展开更多
Exosomes （EXO） derived from dendritic cells （DC） and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison o...Exosomes （EXO） derived from dendritic cells （DC） and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin （OVA） and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCOVA-derived EXO （EXODC） can more efficiently stimulate naive OVA-specific CD8^＋ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO （EXOEG7）. In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity. Cellular ＆ Molecular Immunology. 2006;3（3）：205-211.展开更多
T cells secrete bioactive exosomes(EXO),but the potential immunoregulatory effect of T-cell EXO is largely unknown.In this study,we generated activated ovalbumin(OVA)-specific CD4^(+) T cells in vitro via coculture of...T cells secrete bioactive exosomes(EXO),but the potential immunoregulatory effect of T-cell EXO is largely unknown.In this study,we generated activated ovalbumin(OVA)-specific CD4^(+) T cells in vitro via coculture of OVA-pulsed dendritic cells(DC_(OVA))with naive CD4^(+) T cells derived from OVA-specific T-cell receptor(TCR)transgenic OTII mice.CD4^(+) T-cell EXO were then purified from the CD4^(+) T-cell culture supernatants by differential ultracentrifugation.CD4^(+) T-cell EXO exhibited the‘saucer’shape that is characteristic of EXO with a diameter between 50 and 100 nm,as assessed by electron microscopy,and contained the EXO-associated proteins LAMP-1,TCR and lymphocyte function associated antigen-1(LFA-1),as determined by western blot.Flow cytometric analysis showed that CD4^(+) T-cell EXO expressed CD4^(+) T-cell markers(CD4,TCR,LFA-1,CD25 and Fas ligand),but to a lesser extent than CD4^(+) T cells.We demonstrated that DC_(OVA) took up CD4^(+) T-cell EXO via peptide/major histocompatibility complex(pMHC)II/TCR and CD54/LFA-1 interactions.OVA-specific CD4^(+) T-cell EXO from OTII mice,but not ConA-stimulated polyclonal CD4^(+) T-cell EXO from wild-type C57BL/6 mice inhibited DC_(OVA)-stimulated in vitro CD4^(+) T-cell proliferation and in vivo CD81 cytotoxic T lymphocyte(CTL)responses and antitumor immunity against OVA-expressing B16 melanoma BL6-10OVA cells.In addition,EXO derived from a T-cell hybridoma cell line,MF72.2D9,expressing an OVA-specific CD4^(+) TCR,had a similar inhibitory effect as OTII CD4^(+) T-cell EXO on CTL-mediated antitumor immunity.Taken together,our data indicate that antigen-specific T-cell EXO may serve as a new type of immunosuppressive reagent for use in transplant rejection and treatment of autoimmune diseases.展开更多
Intercellular communication is an important means of molecular information transfer through exchange of membrane proteins from cells to cells. Advent of the latest analytical and imaging tools has allowed us to enhanc...Intercellular communication is an important means of molecular information transfer through exchange of membrane proteins from cells to cells. Advent of the latest analytical and imaging tools has allowed us to enhance our understanding of the cellular communication through the intercellular exchange of intact membrane patches, also called trogocytosis, which is a ubiquitous phenomenon. Immune responses against pathogens or any foreign antigens require fine immune regulation, where cellular communications are mediated by either soluble or cell surface molecules. It has been demonstrated that the membrane molecule transfer between immune cells such as dendritic and T cells can be derived through internalization/recycling pathway, dissociation-associated pathway, uptake of exosomes and membrane nanotube formations. Recent evidence implicates the trogocytosis as an important mechanism of the immune system to modulate immune responses. Exchange of membrane molecules/ antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. In this review, we discuss the possible mechanisms of trogocytosis and its physiological relevance to immune system, with special reference to T cells and the stimulatory or suppressive immune responses derived from T cells with acquired dendritic cell membrane molecules. Cellular ＆ Molecular Immunology. 2008;5（4）：261-269.展开更多
CD8^＋ cytotoxic T （Tc） cells play a crucial role in host immune responses to cancer, and in this context, adoptive CD8^＋ Tc cell therapy has been studied in numerous animal tumor models. Its antitumor efficacy is,...CD8^＋ cytotoxic T （Tc） cells play a crucial role in host immune responses to cancer, and in this context, adoptive CD8^＋ Tc cell therapy has been studied in numerous animal tumor models. Its antitumor efficacy is, to a large extent, determined by the ability of Tc cells to survive and infiltrate tumors. In clinical trials, such in vitro-activated T cells often die within hours to days, and this greatly limits their therapeutic efficacy. CD8^＋ Tc cells fall into two subpopulations based upon their differential cytokine secretion. In this study, we in vitro generated that ovalbumin （OVA）-pulsed dendritic cell （DCovA）-activated CD8^＋ type 1 Tc （Tcl） cells secreting IFN-T, and CD8^＋ type 2 Tc （Tc2） cells secreting IL-4, IL-5 and IL-10, which were derived from OVA-specific T cell receptor （TCR） transgenic OT I mice. We then systemically investigated the in vitro and in vivo effector function and survival of Tcl and Tc2 cells, and then assessed their survival kinetics after adoptively transferred into C57BL/6 mice, respectively. We demonstrated that, when compared to CD8^＋ Tc2, Tcl cells were significantly more effective in perforin-mediated cytotoxicity to tumor cells, had a significantly higher capacity for in vivo survival after the adoptive T cell transfer, and had a significantly stronger therapeutic effect on eradication of well-established tumors expressing OVA in animal models. In addition, CD8^＋ Tcl and Tc2 cells skewed the phenotype of CD4^＋ T cells toward Thl and Th2 type, respectively. Therefore, the information regarding the differential effector function, survival and immune modulation of CD8^＋ Tcl and Tc2 cells may provide useful information when preparing in vitro DC-activated CD8^＋ T cells for adoptive T cell therapy of cancer.展开更多
CD4＋ helper T （Th） cells play pivotal roles in induction of CD8＋ CTL immunity. However, the mechanism of CD4＋ T cell help delivery to CD8＋ T cells in vivo is still elusive. In this study, we used ovalbumin （OVA...CD4＋ helper T （Th） cells play pivotal roles in induction of CD8＋ CTL immunity. However, the mechanism of CD4＋ T cell help delivery to CD8＋ T cells in vivo is still elusive. In this study, we used ovalbumin （OVA）-pulsed dendritic cells （DCovA） to activate OT-II mouse CD4＋ T cells, and then studied the help effect of these CD4＋ T cells on CD8＋ cytotoxic T lymphocyte （CTL） responses＋ We also examined CTL mediated islet β cell destruction which leaded to diabetes in wild-type C57BL/6 mice and transgenic rat insulin promoter （RIP）-mOVA mice expressing β cell antigen OVA with self OVA-specific tolerance, respectively. In adoptive transfer experiments, we demonstrated that help, in the form of peptide/major histocompatibility complex （pMHC） I acquired from DCovA by DCovA activation, was required for induction of OVA-specific CTL responses in C57BL/6 mice. However, in combination ＋ ＋ ＋ with TCR transgenlc OT-I mouse CD8 T ceils, the tolerogenic dosage of CD4＋ Th cells with acquired pMHC I, but not CD4＋ （Kb-/-） Th cells without acquired pMHC I were able to cause diabetes in 8/10 （80%） RIP-mOVA mice. This study thus expands the current knowledge in T cell-mediated autoimmunity and provides insight into the nature of CD4＋ T cell-mediated help in CD8＋ CTL induction. Cellular ＆ Molecular Immunology. 2008;5（6）：407-415.展开更多
The ultimate goal of antitumor vaccines is to develop memory CD8＋ cytotoxic T lymphocytes （CTLs）, which are critical mediators of antitumor immunity. We previously demonstrated that the ovalbumin （OVA）-specific ...The ultimate goal of antitumor vaccines is to develop memory CD8＋ cytotoxic T lymphocytes （CTLs）, which are critical mediators of antitumor immunity. We previously demonstrated that the ovalbumin （OVA）-specific CD4＋ T cell-based （OVA-TExo） vaccine generated using OVA-pulsed dendritic cell （DCovA）-released exosomes （EXOovA） stimulate CTL responses via IL-2 and costimulatory CD80 signaling. To assess the potential involvement of other costimulatory pathways and to define the key constituent of costimulation for memory CTL development, we first immunized wild-type （WT） C57BIJ6 and gene-knockout mice with WT CD4~ OVA-TExo cells or OVA-TExo cells with various molecular deficiencies. We then assessed OVA-specific primary and recall CTL responses using PE-H-2Kb/ 0VA257_264 tetramer and FITC-anti-CD8 antibody staining by flow cytometry. We also examined antitumor immunity against the OVA-expressing B16 melanoma cell line BL6-1OovA. We demonstrated that CD4＋ OVA-TExo cells stimulated more efficient CTL responses compared to DCovA. By assessing primary and recall CTL responses in mice immunized with OVA-TExo or with OVA-TExo lacking the costimulatory molecules CD4OL, 4-1BBL or OX4OL, we demonstrated that these costimulatory signals are dispensable for CTL priming by OVA-TExo. Interestingly, CD4OL, but not 4-1BBL or OX4OL, plays a crucial role in the development of functional memory CTLs against BL6-1OovA tumors. Overall, this work suggests that a novel CD4＋ T cell-based vaccine that is capable of stimulating long-term functional CTL memory via CD40L signaling may represent a novel, efficient approach to antitumor vaccination.展开更多
CD8＋ cytotoxic T lymphocyte （CTL） exhaustion is a chief issue for ineffective virus elimination in chronic infectious diseases. We generated novel ovalbumin （OVA）-specific OVA-Texo and HIV-specific Gag-Texo vacci...CD8＋ cytotoxic T lymphocyte （CTL） exhaustion is a chief issue for ineffective virus elimination in chronic infectious diseases. We generated novel ovalbumin （OVA）-specific OVA-Texo and HIV-specific Gag-Texo vaccines inducing therapeutic immunity. To assess their therapeutic effect in chronic infection, we developed a new chronic infection model by i.v. infecting C57BL/6 mice with the OVA-expressing adenovirus AdVova. During chronic AdVova infection, mouse CTLs were found to express the inhibitory molecules programmed cell-death protein-1 （PD-1） and lymphocyte-activation gene-3 （LAG-3） and to be functionally exhausted, showing a significant deficiency in T-cell proliferation, IFN-7 production and cytolytic effects. Naive CD8＋ T cells upregulated inhibitory PD-ligand 1 （PD-L1）, B- and T-lymphocyte attenuator and T-cell anergy-associated molecules （Grail and Itch） while down-regulating the proliferative response upon stimulation in mice with chronic infection. Remarkably, the OVA-Texo vaccine counteracted T-cell anergy and converted CTL exhaustion. The latter was associated with （i） the upregulation of a marker for CTL functionality, diacetylated histone-H3 （diAcH3）, （ii） a fourfold increase in CTLs, occurring independent of host DCs or CD4＋ T cells, and （iii） the restoration of CTL IFN-7 production and cytotoxicity. In vivo OVA-Texo-stimulated CTLs upregulated the activities of the mTORC1 pathway-related molecules Akt, S6, elF4E and T-bet, and treatment of the CTLs with an mTORC1 inhibitor, rapamycin, significantly reduced the OVA-Texo- induced increase in CTLs. Interestingly, OVA-Texo-mediated CD40L signaling played a critical role in the observed immunological effects. Importantly, the Gag-Texo vaccine induced Gag-specific therapeutic immunity in chronic infection. Therefore, this study should have a serious impact on the development of new therapeutic vaccines for human immunodeficiency virus （HIV-1） infection.展开更多
Dendritic cells （DCs） are the most potent antigen-presenting cells （APCs） for the initiation of antigen （Ag）-specific immune responses. In most studies, mature DCs are generated from bone marrow cells or periphe...Dendritic cells （DCs） are the most potent antigen-presenting cells （APCs） for the initiation of antigen （Ag）-specific immune responses. In most studies, mature DCs are generated from bone marrow cells or peripheral monocytes; in either case, the harvested cells are then cultured in medium containing recombinant GM-CSF, IL-4 and TNF-α for 7-10 days and stimulated with lipopolysaccharide （LPS）. However, this approach is time-consuming and expensive. There is another less cost approach of using immobilized DC cell lines, which can easily grow in the medium. A disadvantage with the immobilized DC cell lines, however, is that they are immature DCs and lack expression of MHC class Ⅱ and costimulatory CD40 and CD80 molecules. This, therefore, limits their capacity for inducing efficient antitumor immunity. In the current study, we investigated the possible efficacy of various stimuli （IL-1β, IFN-γ, TNF-α CpG and LPS） in converting the immature dendritic cell line DC2.4 to mature DCs. Our findings were quite interesting since we demonstrated for the first time that IFN-γ was able to stimulate the maturation of DC2.4 cells. The IFN-γ-activated ovalbumin （OVA）-pulsed DC2.4 cells have capacity to upregulate MHC class Ⅱ, CD40, CD80 and CCR7, and to more efficiently stimulate in vitro and in vivo OVA-specific CD8^＋ T cell responses and antitumor immunity. Therefore, IFN-γ-activated immortal DC2.4 ceils may prove to be useful in the study of DC biology and antitumor immunity.展开更多
Human immunodeficiency virus type-1 （HIV-1）-specific dendritic cell （DC） vaccines have been used in clinical trials. However, they have been found to only induce some degree of immune responses in these studies. W...Human immunodeficiency virus type-1 （HIV-1）-specific dendritic cell （DC） vaccines have been used in clinical trials. However, they have been found to only induce some degree of immune responses in these studies. We previously demonstrated that the HIV-1 Gag-specific Gag-Texo vaccine stimulated Gag-specific effector CD8＋ cytotoxic T lymphocyte （CTL） responses, leading to completely protective, but very limited, therapeutic immunity. In this study, we constructed a recombinant adenoviral vector, adenovirus （AdV）4-1BBL, which expressed mouse 4-1BB ligand （4-1BBL）, and generated transgenic 4-1BBL-engineered OVA-Texo/4.1BSL and Gag-Texo/4.1BSL vaccines by transfecting ovalbumin （OVA）-Texo and Gag-＇rexo cells with AdV4.1BBL, respectively. We demonstrate that the OVA-specific OVA-Texo/4.ZSSL vaccine stimulates more efficient OVA-specific CTL responses （3.26%） compared to OVA-Texo-activated responses （1.98%） in wild-type C57BIJ6 mice and the control OVA-TeXO/Nu, vaccine without transgenic 4-1BBL expression, leading to enhanced therapeutic immunity against 6-day established OVA-expressing B16 melanoma BL6-1OovA cells. OVA-Texo/4.1BBL-stimulated CTLs, which have a CD44＋CD62Lhigh IL-7R＋ phenotype, are likely memory CTL precursors, demonstrating prolonged survival and enhanced differentiation into memory CTLs with functional recall responses and long-term immunity against BL6-1OovA melanoma. In addition, we demonstrate that OVA-Texo/4_ZBBL-Stimulated CTLs up- and downregulate the expression of anti-apoptosis （Bcl2110, Naipl, No13, Pak7 and Tnfrsfllb） and pro-apoptosis （Casp12, Trp63 and Trp73） genes, respectively, by RT2 Profiler PCR array analysis. Importantly, the Gag-specific Gag-Texo/4.1BBL vaccine also stimulates more efficient Gag-specific therapeutic and long-term immunity against HLA-A2/Gag-expressing B 16 melanoma BL6-1OGag/A2 cells than the control Gag-TeXO/NuH vaccine in transgenic HLA-A2 mice. Taken together, our novel Gag-Texo/4-ZBBL vaccine, which is capable of stimulating potent Gag-specific therapeutic and long-term immunity, may represent a new immunotherapeutic vaccine for controlling HIV-1 infection.展开更多
Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 m...Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 mm^(3))and medium distant(100 mm^(3))EG7 lymphomas engineered to express ovalbumin(OVA)as a nominal tumor antigen.We established experimental protocols including IRE alone and IRE combined with Toll-like receptor(TLR)3/9 agonists(poly I:C/CpG)(IRE+pIC/CpG),PD-1 blockade(IRE+PD-1 blockade),or both(IRE+Combo)to investigate therapeutic effects on primary and distant EG7 tumors and conversion-promoting effects on the immunotolerant tumor microenvironment(TME).We demonstrated that IRE alone simulated very weak OVA-specific CD8^(+)T cell responses and did not inhibit primary tumor growth.IRE+pIC/CpG synergistically stimulated more efficient OVA-specific CD8^(+)T cell responses and primary tumor growth inhibition than IRE+PD-1 blockade.IRE+pIC/CpG played a major role in the modulation of immune cell profiles but a minor role in the downregulation of PD-L1 expression in the TME and vice versa for IRE+PD-1 blockade.IRE+Combo cooperatively induced potent OVA-specific CD8^(+)T cell immunity and rescued exhausted intratumoral CD8^(+)T cells,leading to eradication of not only primary tumors but also untreated concomitant distant tumors and lung metastases.IRE+Combo efficiently modulated immune cell profiles,as evidenced by reductions in immunotolerant type-2(M2)macrophages,myeloid-derived suppressor-cells,plasmacytoid dendritic cells,and regulatory T cells and by increases in immunogenic M1 macrophages,CD169^(+)macrophages,type-1 conventional dendritic cells,and CD8^(+)T cells,leading to conversion of immunotolerance in not only primary TMEs but also untreated distant TMEs.IRE+Combo also showed effective therapeutic effects in two breast cancer models.Therefore,our results suggest that IRE+Combo is a promising strategy to improve IRE ablation therapy in cancer.展开更多
Radiofrequency ablation(RFA)is the most common approach to thermal ablation for cancer therapy.Unfortunately,its efficacy is limited by incomplete ablation,and further optimization of RFA is required.Here,we demonstra...Radiofrequency ablation(RFA)is the most common approach to thermal ablation for cancer therapy.Unfortunately,its efficacy is limited by incomplete ablation,and further optimization of RFA is required.Here,we demonstrate that incubation at 65°C triggers more EG7 tumor cell death by necrosis than treatment at 45°C,and the 65°C-treated cells are more effective at inducing antigen-specific CD8^(+)cytotoxic T lymphocyte(CTL)responses after injection in mice than the 45°C-treated ones.Dendritic cells(DCs)that phagocytose 65°C-treated EG7 cells become mature with upregulated MHCII and CD80 expression and are capable of efficiently inducing effector CTLs in mouse tumor models.RFA(65°C)therapy of EG7 tumors induces large areas of tumor necrosis and stimulates CTL responses.This leads to complete regression of small(~100 mm^(3))tumors but fails to suppress the growth of larger(~350 mm^(3))tumors.The administration of the Toll-like receptor-9(TLR9)agonist unmethylated cytosine-phosphorothioate-guanine oligonucleotide(CpG)to DCs phagocytosing 65°C-treated EG7 cells enhances the expression of MHCII and CD40 on DCs as well as DC-induced stimulation of CTL responses.Importantly,the intratumoral administration of CpG following RFA also increases the frequencies of tumor-associated immunogenic CD11b−CD11c^(+)CD103^(+)DC2 and CD11b+F4/80+MHCII+M1 macrophages and increases CD4^(+)and CD8^(+)T-cell tumor infiltration,leading to enhanced CD4^(+)T cell-dependent CTL responses and potent inhibition of primary RFA-treated or distant untreated tumor growth as well as tumor lung metastasis in mice bearing larger tumors.Overall,our data indicate that CpG administration,which enhances RFA-induced CTL responses and ultimately potentiates the inhibition of primary tumor growth and lung metastasis,is a promising strategy for improving RFA treatment,which may assist in optimizing this important cancer therapy.展开更多
CD8^(+)effector T(T_(E))cells play a critical role in immunity against infections.In response to a pathogenic stimulus,antigenpresenting cells(APCs)deliver three signals[via T-cell receptor(TCR),costimulation,and cyto...CD8^(+)effector T(T_(E))cells play a critical role in immunity against infections.In response to a pathogenic stimulus,antigenpresenting cells(APCs)deliver three signals[via T-cell receptor(TCR),costimulation,and cytokines]to naive CD8^(+)T cells,stimulating their entry into a developmental program characterized by T-cell expansion followed by a contraction phase.During the contraction phase,90-95%of IL-7R^(-)CD62L^(-)KLRG1^(+)T_(E)cells undergo cell apoptosis.展开更多
文摘Anti-human epidermal growth factor receptor-2 (HER2) immunization can be elicited by vaccination with DNA encoding the extra- or intra-cellular domain (ECD or ICD) of HER2, naked or encap-sulated in viral vectors. HER2-peptides derived from ECD or ICD of HER2, and HER2-pulsed dendritic cells (DCs) or engineered DCs expressing HER2, respectively. We performed a computer- based literature search which includes but is not limited to the following keywords: breast cancer, immunotherapy, HER2-peptide vaccine, HER2-DNA vaccine, HER-DC vaccine, HER2 vaccine, and HER2/neu, in PubMed, Medline, EMBO and Google Scholar;data from recently reported clinical trials were also included. Drawing upon this synthesis of literature, this work summarizes the de-velopment and current trend in experimental and clinical investigations in HER2-positive breast cancer using HER2-specific vaccine and immunotherapy, focusing especially on: (i) DNA-;(ii) peptide-;and (iii) DC-based vaccines. It addresses interventions that have been applied to overcome immunotolerance thereby to improve treatment outcomes. These include blocking the inhibitory cytotoxic T lymphocyte-associated protein-4 (CTLA-4), which is expressed at high levels by regulatory T (Treg) cells, or complete Treg depletion to improve T-cell activation. Moreover, modulatory interventions can provide further improvement in the efficacy of HER2-specific vaccine. The interventions include the use of immunogenic adjuvants such as cytokines interleukin-12 (IL-12), tumor necrosis factor (TNF)-α and granulocyte-macrophage colony-stimulating factor (GM-CSF), the use of Toll-like receptor (TLR) ligands and tetanus toxin’s universal epitopes such as the CD4+ help T (Th)-epitope P30, and the use of either chimeric or heterogenous xenogeneic HER2. Combining active HER2-vaccination with adoptive trastuzumab antibody immunotherapy is likely to increase the effectiveness of each approach alone. The development of effective HER2-vaccines for breast cancer remains a critical challenge. Though these novel interventions seem promising, further investigation is still needed since the results are preliminary. Furthermore, the review discusses the challenges and future perspectives in HER2-vaccine research and development.
文摘Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor suppressor genes. Central to all these therapies is the development of efficient vectors for gene therapy. By far, adenovirus （AdV）-mediated gene therapy is one of the most promising approaches, as has confirmed by studies relating to animal tumor models and clinical trials. Dendritic cells （DCs） are highly efficient, specialized antigen-presenting cells, and DC- based tumor vaccines are regarded as having much potential in cancer immunotherapy. Vaccination with DCs pulsed with tumor peptides, lysates, or RNA, or loaded with apoptotic/necrotic tumor cells, or engineered to express certain cytokines or chemokines could induce significant antitumor cytotoxic T lymphocyte （CTL） responses and antitumor immunity. Although both AdV-mediated gene therapy and DC vaccine can both stimulate antitumor immune responses, their therapeutic efficiency has been limited to generation of prophylactic antitumor immunity against re-challenge with the parental tumor cells or to growth inhibition of small tumors. However, this approach has been unsuccessful in combating well-established tumors in animal models. Therefore, a major strategic goal of current cancer immunotherapy has become the development of novel therapeutic strategies that can combat well-established tumors, thus resembling real clinical practice since a good proportion of cancer patients generally present with significant disease. In this paper, we review the recent progress in AdV-mediated cancer gene therapy and DC-based cancer vaccines, and discuss combined immunotherapy including gene therapy and DC vaccines. We underscore the fact that combined therapy may have some advantages in combating well-established tumors vis-a-vis either modality administered as a monotherapy.
文摘Human immunodeficiency virus type-1 (HIV-1) chronic infection causes millions of deaths each year. We previously developed a novel HIV-1 Gag-spe cific exosome (EXO)-targeted T cell-based vaccine (Gag-Texo) using ConAstimulated polyclonal CD8+T (ConA-T) cells armed with Gag-specific dendritic cell (DC)-released EXOs, and showed that Gag-Texo stimulated more efficient cytotoxic T lymphocyte (CTL) responses than DCs. Tat HIV-1 early regulatory protein possesses immunomodulatory and adjuvant properties. To enhance Gag-Texo immunogenicity, we generated Tat-engineered OVA/Tat Texo and Gag/Tat-Texo vaccines using ConA-T cells armed with EXOs release by DCs infected with recombinant OVA/Tat- and Gag/Tat-expressing adenoviruses (AdVOVA/Tat and AdVGag/Tat). We then assessed vaccination-stimulated CTL responses in naive mice, and therapeutic immunity in transgenic HLA-A2 mice bearing Gag/HLA-A2-expressing BL6-10OVA/A2 melanoma lung metastases. We demonstrate that the OVA/Tat-Texo vaccine enhances functional OVA-specific CTL responses, compared to the OVA-Texo vaccine, and broadens CTL responses recognizing the cryptic OVA epitope in C57BL/6 mice. Furthermore, we determine that the Gag/Tat-Texo not only stimulates more efficient CTL responses than Gag-Texo, but also induces enhanced therapeutic immunity. We show that, 30% of Gag/Tat-Texo-immunized mice are free of tumor lung-metastases, compared to all Gag-Texo-immunized mice displaying lung-metastasis. In addition, the average number of tumor lung metastases colonies (32/lung) in the Gag/Tat-Texo-immunized mice was also significantly lower than that (78/lung) observed in Gag-Texo-immunized mice. Taken together, this indicates that HIV-1 Gag/Tat-Texo capable of stimulating enhanced Gag-specific CTL responses and therapeutic immunity may become a new immunotherapeutic vaccine candidate for controlling virus in HIV-1 patients.
文摘BACKGROUND: We assessed whether the paediatric-appropriate facilities were available at Emergency Departments(ED) in community hospitals in a Canadian province.METHODS: We conducted a cross-sectional survey of EDs in community hospitals in Ontario, Canada that had inpatient paediatric facilities and a neonatal intensive care unit. Key informants were ED chiefs, clinical educators, or managers. The survey included questions about paediatric facilities related to environment, triage, training, and staff in EDs.RESULTS: Of 52 hospitals, 69%(n=36) responded to our survey. Of them, 14% EDs(n=5) had some separated spaces available for paediatric patients. About 53%(n=19) of EDs lacked children activities, e.g., toys. Only 11%(n=4) EDs were using paediatric triage scales and 42%(n=15) had a designated paediatric resuscitation bay. Only half of the ED(n=18) required from their staff to update paediatric life support training. Only 31%(n=11) had a designated liaison paediatrician for the ED. Paediatric social worker was present in only 8%(n=3) of EDs in community hospitals.CONCLUSION: Most of the Ontario community hospital EDs included in this survey had inadequate facilities for paediatric patients such as specific waiting and treatment areas.
文摘CD8+ cytotoxic T lymphocyte (CTL) exhaustion is one of the major obstacles for the effectiveness of virus control in chronic infectious diseases. We previously generated novel ovalbumin (OVA)-specific 41BBL-expressing OVA-TEXO and human immunodeficiency virus (HIV-1) Gag-specific Gag-TEXO vaccines, inducing therapeutic immunity in wild-type C57BL/6 (B6) mice, and converting CTL exhaustion in recombinant OVA-specific adenovirus AdVOVA-infected B6 (AdVOVA-B6) mice with chronic infection. IL-21 cytokine plays an important role in controlling chronic infections. Therefore, in this study, we constructed recombinant transgene IL-21-expressing AdVIL-21, and generated IL-21-expressing OVA-TEXO/IL-21 and Gag-TEXO/IL21 vaccines, or control vaccines (OVA-TEXO/Null and Gag-TEXO/Null) by infecting OVA-TEXO and Gag-TEXO cells with AdVIL-21 or the control AdVNull, lacking transgene, and assessed their effects in B6 or AdVOVA-B6 mice. We demonstrate that both OVA-TEXO/IL-21 and control OVA-TEXO/Null vaccines are capable of converting CTL exhaustion in chronic infection. However, the OVA-TEXO/IL-21 vaccine more efficiently rescues exhausted CTLs by increasing stronger CTL proliferation and effector cytokine IFN-γ expression than the control OVA-TEXO/Null vaccine in AdVOVA-B6 mice with chronic infection, though both vaccines stimulated comparable OVA-specific CTL responses and protective immunity against OVA-expressing BL6-10OVA melanoma lung metastasis in wild-type B6 mice. In vivo, the OVA-TEXO/IL-21-stimulated CTLs more efficiently up-regulate phosphorylation of mTORC1-controlled EIF4E and expression of mTORC1- regulated T-bet molecule than the control OVA-TEXO/Null-stimulated ones. Importantly, the Gag-TEXO/IL21 vaccine induces stronger Gag-specific therapeutic immunity against established Gag-expressing BL6-10Gag melanoma lung metastases than the control Gag-TEXO/Null vaccine in chronic infection. Therefore, this study should have a strong impact on developing new therapeutic vaccines for patients with chronic infections.
文摘The occurrence of multiple primary cancers is rare;it can be missed as a disease progression. The etiology remains controversial. We report a case of a 55-year-old female with metastatic renal cell carcinoma treated with sutent followed by left sided nephrectomy. Follow-up CT showed increase in the size of the right axillary lymph nodes which was proven after biopsy to be metastatic adenocarcinoma of the breast. Any suspicious disease progression in a single site not compatible with disease history should be biopsied for confirmation. The relationship between renal cell carcinoma and breast cancer is still unclear, and more case reports are required to determine this relationship.
文摘Introduction: Leukemoid reactions in cancer are rare and associated with a poor prognosis. The mechanism driving paraneoplastic leukemoid reactions appears to be gain-of-function granulocyte-colony stimulating factor (G-CSF) secretion by tumour cells. Case Presentation: A 57-year-old male smoker presented with a one-year history of painless frank hematuria and three kilograms weight loss. Cystoscopy revealed a high-grade urothelial carcinoma with sarcomatoid differentiation. The patient was treated by radical cystoprostatectomy, bilateral pelvic lymph node dissection and formation of an ileal conduit. In the absence of bone marrow infiltrations, recurrence of the urothelial carcinoma three months later was associated with a paraneoplastic leukemoid reaction with a white blood cell count peaking at 82.62 × 109/l. Unfortunately, his condition continued to deteriorate and he died shortly thereafter. Conclusion: Monitoring of white blood cell counts in paraneoplastic leukemoid reactions can be a useful indicator of response of the malignancy to chemotherapy or radiotherapy and an indication of relapse after treatment. Paraneoplastic leukemoid reactions are caused by G-CSF secretion by tumour cells and are associated with a poor prognosis. Whether G-CSF signaling plays a role in the aggressive nature of these cancers is currently unknown.
文摘Exosomes （EXO） derived from dendritic cells （DC） and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin （OVA） and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCOVA-derived EXO （EXODC） can more efficiently stimulate naive OVA-specific CD8^＋ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO （EXOEG7）. In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity. Cellular ＆ Molecular Immunology. 2006;3（3）：205-211.
基金This study was supported by research grants from the Canadian Institutes of Health Research(MOP 79415 and 89713).
文摘T cells secrete bioactive exosomes(EXO),but the potential immunoregulatory effect of T-cell EXO is largely unknown.In this study,we generated activated ovalbumin(OVA)-specific CD4^(+) T cells in vitro via coculture of OVA-pulsed dendritic cells(DC_(OVA))with naive CD4^(+) T cells derived from OVA-specific T-cell receptor(TCR)transgenic OTII mice.CD4^(+) T-cell EXO were then purified from the CD4^(+) T-cell culture supernatants by differential ultracentrifugation.CD4^(+) T-cell EXO exhibited the‘saucer’shape that is characteristic of EXO with a diameter between 50 and 100 nm,as assessed by electron microscopy,and contained the EXO-associated proteins LAMP-1,TCR and lymphocyte function associated antigen-1(LFA-1),as determined by western blot.Flow cytometric analysis showed that CD4^(+) T-cell EXO expressed CD4^(+) T-cell markers(CD4,TCR,LFA-1,CD25 and Fas ligand),but to a lesser extent than CD4^(+) T cells.We demonstrated that DC_(OVA) took up CD4^(+) T-cell EXO via peptide/major histocompatibility complex(pMHC)II/TCR and CD54/LFA-1 interactions.OVA-specific CD4^(+) T-cell EXO from OTII mice,but not ConA-stimulated polyclonal CD4^(+) T-cell EXO from wild-type C57BL/6 mice inhibited DC_(OVA)-stimulated in vitro CD4^(+) T-cell proliferation and in vivo CD81 cytotoxic T lymphocyte(CTL)responses and antitumor immunity against OVA-expressing B16 melanoma BL6-10OVA cells.In addition,EXO derived from a T-cell hybridoma cell line,MF72.2D9,expressing an OVA-specific CD4^(+) TCR,had a similar inhibitory effect as OTII CD4^(+) T-cell EXO on CTL-mediated antitumor immunity.Taken together,our data indicate that antigen-specific T-cell EXO may serve as a new type of immunosuppressive reagent for use in transplant rejection and treatment of autoimmune diseases.
文摘Intercellular communication is an important means of molecular information transfer through exchange of membrane proteins from cells to cells. Advent of the latest analytical and imaging tools has allowed us to enhance our understanding of the cellular communication through the intercellular exchange of intact membrane patches, also called trogocytosis, which is a ubiquitous phenomenon. Immune responses against pathogens or any foreign antigens require fine immune regulation, where cellular communications are mediated by either soluble or cell surface molecules. It has been demonstrated that the membrane molecule transfer between immune cells such as dendritic and T cells can be derived through internalization/recycling pathway, dissociation-associated pathway, uptake of exosomes and membrane nanotube formations. Recent evidence implicates the trogocytosis as an important mechanism of the immune system to modulate immune responses. Exchange of membrane molecules/ antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. In this review, we discuss the possible mechanisms of trogocytosis and its physiological relevance to immune system, with special reference to T cells and the stimulatory or suppressive immune responses derived from T cells with acquired dendritic cell membrane molecules. Cellular ＆ Molecular Immunology. 2008;5（4）：261-269.
文摘CD8^＋ cytotoxic T （Tc） cells play a crucial role in host immune responses to cancer, and in this context, adoptive CD8^＋ Tc cell therapy has been studied in numerous animal tumor models. Its antitumor efficacy is, to a large extent, determined by the ability of Tc cells to survive and infiltrate tumors. In clinical trials, such in vitro-activated T cells often die within hours to days, and this greatly limits their therapeutic efficacy. CD8^＋ Tc cells fall into two subpopulations based upon their differential cytokine secretion. In this study, we in vitro generated that ovalbumin （OVA）-pulsed dendritic cell （DCovA）-activated CD8^＋ type 1 Tc （Tcl） cells secreting IFN-T, and CD8^＋ type 2 Tc （Tc2） cells secreting IL-4, IL-5 and IL-10, which were derived from OVA-specific T cell receptor （TCR） transgenic OT I mice. We then systemically investigated the in vitro and in vivo effector function and survival of Tcl and Tc2 cells, and then assessed their survival kinetics after adoptively transferred into C57BL/6 mice, respectively. We demonstrated that, when compared to CD8^＋ Tc2, Tcl cells were significantly more effective in perforin-mediated cytotoxicity to tumor cells, had a significantly higher capacity for in vivo survival after the adoptive T cell transfer, and had a significantly stronger therapeutic effect on eradication of well-established tumors expressing OVA in animal models. In addition, CD8^＋ Tcl and Tc2 cells skewed the phenotype of CD4^＋ T cells toward Thl and Th2 type, respectively. Therefore, the information regarding the differential effector function, survival and immune modulation of CD8^＋ Tcl and Tc2 cells may provide useful information when preparing in vitro DC-activated CD8^＋ T cells for adoptive T cell therapy of cancer.
基金supported by research funds from Canadian Institute of Health Research (MOP 79415, 81228 and 89713)
文摘CD4＋ helper T （Th） cells play pivotal roles in induction of CD8＋ CTL immunity. However, the mechanism of CD4＋ T cell help delivery to CD8＋ T cells in vivo is still elusive. In this study, we used ovalbumin （OVA）-pulsed dendritic cells （DCovA） to activate OT-II mouse CD4＋ T cells, and then studied the help effect of these CD4＋ T cells on CD8＋ cytotoxic T lymphocyte （CTL） responses＋ We also examined CTL mediated islet β cell destruction which leaded to diabetes in wild-type C57BL/6 mice and transgenic rat insulin promoter （RIP）-mOVA mice expressing β cell antigen OVA with self OVA-specific tolerance, respectively. In adoptive transfer experiments, we demonstrated that help, in the form of peptide/major histocompatibility complex （pMHC） I acquired from DCovA by DCovA activation, was required for induction of OVA-specific CTL responses in C57BL/6 mice. However, in combination ＋ ＋ ＋ with TCR transgenlc OT-I mouse CD8 T ceils, the tolerogenic dosage of CD4＋ Th cells with acquired pMHC I, but not CD4＋ （Kb-/-） Th cells without acquired pMHC I were able to cause diabetes in 8/10 （80%） RIP-mOVA mice. This study thus expands the current knowledge in T cell-mediated autoimmunity and provides insight into the nature of CD4＋ T cell-mediated help in CD8＋ CTL induction. Cellular ＆ Molecular Immunology. 2008;5（6）：407-415.
文摘The ultimate goal of antitumor vaccines is to develop memory CD8＋ cytotoxic T lymphocytes （CTLs）, which are critical mediators of antitumor immunity. We previously demonstrated that the ovalbumin （OVA）-specific CD4＋ T cell-based （OVA-TExo） vaccine generated using OVA-pulsed dendritic cell （DCovA）-released exosomes （EXOovA） stimulate CTL responses via IL-2 and costimulatory CD80 signaling. To assess the potential involvement of other costimulatory pathways and to define the key constituent of costimulation for memory CTL development, we first immunized wild-type （WT） C57BIJ6 and gene-knockout mice with WT CD4~ OVA-TExo cells or OVA-TExo cells with various molecular deficiencies. We then assessed OVA-specific primary and recall CTL responses using PE-H-2Kb/ 0VA257_264 tetramer and FITC-anti-CD8 antibody staining by flow cytometry. We also examined antitumor immunity against the OVA-expressing B16 melanoma cell line BL6-1OovA. We demonstrated that CD4＋ OVA-TExo cells stimulated more efficient CTL responses compared to DCovA. By assessing primary and recall CTL responses in mice immunized with OVA-TExo or with OVA-TExo lacking the costimulatory molecules CD4OL, 4-1BBL or OX4OL, we demonstrated that these costimulatory signals are dispensable for CTL priming by OVA-TExo. Interestingly, CD4OL, but not 4-1BBL or OX4OL, plays a crucial role in the development of functional memory CTLs against BL6-1OovA tumors. Overall, this work suggests that a novel CD4＋ T cell-based vaccine that is capable of stimulating long-term functional CTL memory via CD40L signaling may represent a novel, efficient approach to antitumor vaccination.
文摘CD8＋ cytotoxic T lymphocyte （CTL） exhaustion is a chief issue for ineffective virus elimination in chronic infectious diseases. We generated novel ovalbumin （OVA）-specific OVA-Texo and HIV-specific Gag-Texo vaccines inducing therapeutic immunity. To assess their therapeutic effect in chronic infection, we developed a new chronic infection model by i.v. infecting C57BL/6 mice with the OVA-expressing adenovirus AdVova. During chronic AdVova infection, mouse CTLs were found to express the inhibitory molecules programmed cell-death protein-1 （PD-1） and lymphocyte-activation gene-3 （LAG-3） and to be functionally exhausted, showing a significant deficiency in T-cell proliferation, IFN-7 production and cytolytic effects. Naive CD8＋ T cells upregulated inhibitory PD-ligand 1 （PD-L1）, B- and T-lymphocyte attenuator and T-cell anergy-associated molecules （Grail and Itch） while down-regulating the proliferative response upon stimulation in mice with chronic infection. Remarkably, the OVA-Texo vaccine counteracted T-cell anergy and converted CTL exhaustion. The latter was associated with （i） the upregulation of a marker for CTL functionality, diacetylated histone-H3 （diAcH3）, （ii） a fourfold increase in CTLs, occurring independent of host DCs or CD4＋ T cells, and （iii） the restoration of CTL IFN-7 production and cytotoxicity. In vivo OVA-Texo-stimulated CTLs upregulated the activities of the mTORC1 pathway-related molecules Akt, S6, elF4E and T-bet, and treatment of the CTLs with an mTORC1 inhibitor, rapamycin, significantly reduced the OVA-Texo- induced increase in CTLs. Interestingly, OVA-Texo-mediated CD40L signaling played a critical role in the observed immunological effects. Importantly, the Gag-Texo vaccine induced Gag-specific therapeutic immunity in chronic infection. Therefore, this study should have a serious impact on the development of new therapeutic vaccines for human immunodeficiency virus （HIV-1） infection.
文摘Dendritic cells （DCs） are the most potent antigen-presenting cells （APCs） for the initiation of antigen （Ag）-specific immune responses. In most studies, mature DCs are generated from bone marrow cells or peripheral monocytes; in either case, the harvested cells are then cultured in medium containing recombinant GM-CSF, IL-4 and TNF-α for 7-10 days and stimulated with lipopolysaccharide （LPS）. However, this approach is time-consuming and expensive. There is another less cost approach of using immobilized DC cell lines, which can easily grow in the medium. A disadvantage with the immobilized DC cell lines, however, is that they are immature DCs and lack expression of MHC class Ⅱ and costimulatory CD40 and CD80 molecules. This, therefore, limits their capacity for inducing efficient antitumor immunity. In the current study, we investigated the possible efficacy of various stimuli （IL-1β, IFN-γ, TNF-α CpG and LPS） in converting the immature dendritic cell line DC2.4 to mature DCs. Our findings were quite interesting since we demonstrated for the first time that IFN-γ was able to stimulate the maturation of DC2.4 cells. The IFN-γ-activated ovalbumin （OVA）-pulsed DC2.4 cells have capacity to upregulate MHC class Ⅱ, CD40, CD80 and CCR7, and to more efficiently stimulate in vitro and in vivo OVA-specific CD8^＋ T cell responses and antitumor immunity. Therefore, IFN-γ-activated immortal DC2.4 ceils may prove to be useful in the study of DC biology and antitumor immunity.
文摘Human immunodeficiency virus type-1 （HIV-1）-specific dendritic cell （DC） vaccines have been used in clinical trials. However, they have been found to only induce some degree of immune responses in these studies. We previously demonstrated that the HIV-1 Gag-specific Gag-Texo vaccine stimulated Gag-specific effector CD8＋ cytotoxic T lymphocyte （CTL） responses, leading to completely protective, but very limited, therapeutic immunity. In this study, we constructed a recombinant adenoviral vector, adenovirus （AdV）4-1BBL, which expressed mouse 4-1BB ligand （4-1BBL）, and generated transgenic 4-1BBL-engineered OVA-Texo/4.1BSL and Gag-Texo/4.1BSL vaccines by transfecting ovalbumin （OVA）-Texo and Gag-＇rexo cells with AdV4.1BBL, respectively. We demonstrate that the OVA-specific OVA-Texo/4.ZSSL vaccine stimulates more efficient OVA-specific CTL responses （3.26%） compared to OVA-Texo-activated responses （1.98%） in wild-type C57BIJ6 mice and the control OVA-TeXO/Nu, vaccine without transgenic 4-1BBL expression, leading to enhanced therapeutic immunity against 6-day established OVA-expressing B16 melanoma BL6-1OovA cells. OVA-Texo/4.1BBL-stimulated CTLs, which have a CD44＋CD62Lhigh IL-7R＋ phenotype, are likely memory CTL precursors, demonstrating prolonged survival and enhanced differentiation into memory CTLs with functional recall responses and long-term immunity against BL6-1OovA melanoma. In addition, we demonstrate that OVA-Texo/4_ZBBL-Stimulated CTLs up- and downregulate the expression of anti-apoptosis （Bcl2110, Naipl, No13, Pak7 and Tnfrsfllb） and pro-apoptosis （Casp12, Trp63 and Trp73） genes, respectively, by RT2 Profiler PCR array analysis. Importantly, the Gag-specific Gag-Texo/4.1BBL vaccine also stimulates more efficient Gag-specific therapeutic and long-term immunity against HLA-A2/Gag-expressing B 16 melanoma BL6-1OGag/A2 cells than the control Gag-TeXO/NuH vaccine in transgenic HLA-A2 mice. Taken together, our novel Gag-Texo/4-ZBBL vaccine, which is capable of stimulating potent Gag-specific therapeutic and long-term immunity, may represent a new immunotherapeutic vaccine for controlling HIV-1 infection.
文摘Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 mm^(3))and medium distant(100 mm^(3))EG7 lymphomas engineered to express ovalbumin(OVA)as a nominal tumor antigen.We established experimental protocols including IRE alone and IRE combined with Toll-like receptor(TLR)3/9 agonists(poly I:C/CpG)(IRE+pIC/CpG),PD-1 blockade(IRE+PD-1 blockade),or both(IRE+Combo)to investigate therapeutic effects on primary and distant EG7 tumors and conversion-promoting effects on the immunotolerant tumor microenvironment(TME).We demonstrated that IRE alone simulated very weak OVA-specific CD8^(+)T cell responses and did not inhibit primary tumor growth.IRE+pIC/CpG synergistically stimulated more efficient OVA-specific CD8^(+)T cell responses and primary tumor growth inhibition than IRE+PD-1 blockade.IRE+pIC/CpG played a major role in the modulation of immune cell profiles but a minor role in the downregulation of PD-L1 expression in the TME and vice versa for IRE+PD-1 blockade.IRE+Combo cooperatively induced potent OVA-specific CD8^(+)T cell immunity and rescued exhausted intratumoral CD8^(+)T cells,leading to eradication of not only primary tumors but also untreated concomitant distant tumors and lung metastases.IRE+Combo efficiently modulated immune cell profiles,as evidenced by reductions in immunotolerant type-2(M2)macrophages,myeloid-derived suppressor-cells,plasmacytoid dendritic cells,and regulatory T cells and by increases in immunogenic M1 macrophages,CD169^(+)macrophages,type-1 conventional dendritic cells,and CD8^(+)T cells,leading to conversion of immunotolerance in not only primary TMEs but also untreated distant TMEs.IRE+Combo also showed effective therapeutic effects in two breast cancer models.Therefore,our results suggest that IRE+Combo is a promising strategy to improve IRE ablation therapy in cancer.
基金supported by grants from CoMRAD(#417578)College of Medicine,University of Saskatchewan,Prostate Cancer Fight Foundation(#417782)+1 种基金Royal University Hospital Research Foundation(#417450)Saskatchewan Health Research Foundation(#418672).
文摘Radiofrequency ablation(RFA)is the most common approach to thermal ablation for cancer therapy.Unfortunately,its efficacy is limited by incomplete ablation,and further optimization of RFA is required.Here,we demonstrate that incubation at 65°C triggers more EG7 tumor cell death by necrosis than treatment at 45°C,and the 65°C-treated cells are more effective at inducing antigen-specific CD8^(+)cytotoxic T lymphocyte(CTL)responses after injection in mice than the 45°C-treated ones.Dendritic cells(DCs)that phagocytose 65°C-treated EG7 cells become mature with upregulated MHCII and CD80 expression and are capable of efficiently inducing effector CTLs in mouse tumor models.RFA(65°C)therapy of EG7 tumors induces large areas of tumor necrosis and stimulates CTL responses.This leads to complete regression of small(~100 mm^(3))tumors but fails to suppress the growth of larger(~350 mm^(3))tumors.The administration of the Toll-like receptor-9(TLR9)agonist unmethylated cytosine-phosphorothioate-guanine oligonucleotide(CpG)to DCs phagocytosing 65°C-treated EG7 cells enhances the expression of MHCII and CD40 on DCs as well as DC-induced stimulation of CTL responses.Importantly,the intratumoral administration of CpG following RFA also increases the frequencies of tumor-associated immunogenic CD11b−CD11c^(+)CD103^(+)DC2 and CD11b+F4/80+MHCII+M1 macrophages and increases CD4^(+)and CD8^(+)T-cell tumor infiltration,leading to enhanced CD4^(+)T cell-dependent CTL responses and potent inhibition of primary RFA-treated or distant untreated tumor growth as well as tumor lung metastasis in mice bearing larger tumors.Overall,our data indicate that CpG administration,which enhances RFA-induced CTL responses and ultimately potentiates the inhibition of primary tumor growth and lung metastasis,is a promising strategy for improving RFA treatment,which may assist in optimizing this important cancer therapy.
基金This work was supported by a research grant(#PJT153314)from the Canadian Institute of Health Research(CIHR).
文摘CD8^(+)effector T(T_(E))cells play a critical role in immunity against infections.In response to a pathogenic stimulus,antigenpresenting cells(APCs)deliver three signals[via T-cell receptor(TCR),costimulation,and cytokines]to naive CD8^(+)T cells,stimulating their entry into a developmental program characterized by T-cell expansion followed by a contraction phase.During the contraction phase,90-95%of IL-7R^(-)CD62L^(-)KLRG1^(+)T_(E)cells undergo cell apoptosis.
