Abnormal NKG2D ligand expression has been implicated in the initiation and maintenance of various auto-inflammatory disorders including systemic lupus erythematosus (SLE). This study’s goal was to identify the cellul...Abnormal NKG2D ligand expression has been implicated in the initiation and maintenance of various auto-inflammatory disorders including systemic lupus erythematosus (SLE). This study’s goal was to identify the cellular contexts providing NKG2D ligands for stimulation of the immunosuppressive NKG2D+CD4 T cell subset that has been implicated in modulating juvenile-onset SLE disease activity. Although previous observations with NKG2D+CD4 T cells in healthy individuals pointed towards peripheral B cell and myeloid cell compartments as possible sites of enhanced NKG2DL presence, we found no evidence for a disease-associated increase of NKG2DL-positivity among juvenile-onset SLE B cells and monocytes. However, juvenile-onset SLE patient plasma and matched urine samples were positive by ELISA for the soluble form of the NKG2D ligands MICA and MICB, suggesting that kidney and/or peripheral blood may constitute the NKG2DL positive microenvironments driving NKG2D+CD4 T cell population expansions in this disease.展开更多
Toxoplasma gondii (T. gondii) is a parasite responsible of toxoplasmosis, a disease often asymptomatic but with serious consequences in pregnant women and immunocompromised subjects. Objective: This study aimed to inv...Toxoplasma gondii (T. gondii) is a parasite responsible of toxoplasmosis, a disease often asymptomatic but with serious consequences in pregnant women and immunocompromised subjects. Objective: This study aimed to investigate the impact of T. gondii infection on CD4+ T lymphocytes count in HIV-infected pregnant women. Methods: This was a cross-sectional study of pregnant women co-infected by HIV and T. gondii. The study was conducted from January to July 2016 at the Prevention of Mother-to-Child Transmission of HIV (PMTCT) sites in the Health District of Lacs in Togo. Diagnosis of HIV was performed by immuno-chromatographic methods with Determine TM HIV-1/2 and immuno-filtration with Tri-Dot HIV-1 and 2 kits. Presence of anti-toxoplasmic IgG and IgM antibodies was established via enzyme immunoassay using ELISA-BIOREX®kit. Flow cytometry was used to count CD4+ T lymphocytes. Results: Our study found that of the 4599 pregnant women, 111 (2.41%) were HIV-positive. Among them, 109 (98.20%) were infected by HIV-1 and 2 (1.98%) by HIV-2. Antibodies against T. gondii were detected in 5.36% (IgM), 25% (IgG) and 3.57% (both IgM and IgG) of HIV 56 infected women. There was no significant difference between CD4 cell count in HIV (+)/T. gondii IgM (-)/IgG (-) infected pregnant women (378.8 ± 222.8 cell//μl) compared to HIV (+)/T. gondii/IgM (+) (457.3 ± 183.3 cell//μl), HIV (+)/T. gondii IgG (+) (419.4 ± 287.3 cell//μl) and HIV (+)/T. gondii IgM/IgG (+) (480.5 ± 252.4 cell/μl). Conclusion: This study showed that intracellular parasite T. gondii did not alter CD4+ T lymphocytes count in HIV/T. gondii co-infected pregnant women.展开更多
We have reported a new innate-like CD4 T cell population that expresses cell surface makers of effector/memory cells and produce Th1 and Th2 cytokines immediately upon activation. Unlike conventional CD4 T cells that ...We have reported a new innate-like CD4 T cell population that expresses cell surface makers of effector/memory cells and produce Th1 and Th2 cytokines immediately upon activation. Unlike conventional CD4 T cells that are selected by thymic epithelial cells, these CD4 T cells, named T-CD4 T cells, are selected by MHC class II expressing thymocytes. Previously, we showed that the presence of T-CD4 T cells protected mice from airway inflammation suggesting an immune regulatory role of T-CD4 T cells. To further understand the function of T-CD4 T cells, we investigated immune responses mediated by T-CD4 T cells during bacterial infection because the generation of antigen specific CD4 T cells contributes to clearance of infection and for the development of immune memory. The current study shows a suppressive effect of T-CD4 T cells on both CD8 and CD4 T cell-mediated immune responses during Listeria and Helicobacter infections. In the mouse model of Listeria monocytogenes infection, T-CD4 T cells resulted in decreasedfrequency of Listeria-specific CD8 T cells and the killing activity of them. Furthermore, mice with T-CD4 T cells developed poor immune memory, demonstrated by reduced expansion of antigen-specific T cells and high bacterial burden upon re-infection. Similarly, the presence of T-CD4 T cells suppressed the generation of antigen-specific CD4 T cells in Helicobacter pylori infected mice. Thus, our studies reveal a novel function of T-CD4 T cells in sup-pressing anti-bacterial immunity.展开更多
文摘Abnormal NKG2D ligand expression has been implicated in the initiation and maintenance of various auto-inflammatory disorders including systemic lupus erythematosus (SLE). This study’s goal was to identify the cellular contexts providing NKG2D ligands for stimulation of the immunosuppressive NKG2D+CD4 T cell subset that has been implicated in modulating juvenile-onset SLE disease activity. Although previous observations with NKG2D+CD4 T cells in healthy individuals pointed towards peripheral B cell and myeloid cell compartments as possible sites of enhanced NKG2DL presence, we found no evidence for a disease-associated increase of NKG2DL-positivity among juvenile-onset SLE B cells and monocytes. However, juvenile-onset SLE patient plasma and matched urine samples were positive by ELISA for the soluble form of the NKG2D ligands MICA and MICB, suggesting that kidney and/or peripheral blood may constitute the NKG2DL positive microenvironments driving NKG2D+CD4 T cell population expansions in this disease.
文摘Toxoplasma gondii (T. gondii) is a parasite responsible of toxoplasmosis, a disease often asymptomatic but with serious consequences in pregnant women and immunocompromised subjects. Objective: This study aimed to investigate the impact of T. gondii infection on CD4+ T lymphocytes count in HIV-infected pregnant women. Methods: This was a cross-sectional study of pregnant women co-infected by HIV and T. gondii. The study was conducted from January to July 2016 at the Prevention of Mother-to-Child Transmission of HIV (PMTCT) sites in the Health District of Lacs in Togo. Diagnosis of HIV was performed by immuno-chromatographic methods with Determine TM HIV-1/2 and immuno-filtration with Tri-Dot HIV-1 and 2 kits. Presence of anti-toxoplasmic IgG and IgM antibodies was established via enzyme immunoassay using ELISA-BIOREX®kit. Flow cytometry was used to count CD4+ T lymphocytes. Results: Our study found that of the 4599 pregnant women, 111 (2.41%) were HIV-positive. Among them, 109 (98.20%) were infected by HIV-1 and 2 (1.98%) by HIV-2. Antibodies against T. gondii were detected in 5.36% (IgM), 25% (IgG) and 3.57% (both IgM and IgG) of HIV 56 infected women. There was no significant difference between CD4 cell count in HIV (+)/T. gondii IgM (-)/IgG (-) infected pregnant women (378.8 ± 222.8 cell//μl) compared to HIV (+)/T. gondii/IgM (+) (457.3 ± 183.3 cell//μl), HIV (+)/T. gondii IgG (+) (419.4 ± 287.3 cell//μl) and HIV (+)/T. gondii IgM/IgG (+) (480.5 ± 252.4 cell/μl). Conclusion: This study showed that intracellular parasite T. gondii did not alter CD4+ T lymphocytes count in HIV/T. gondii co-infected pregnant women.
文摘We have reported a new innate-like CD4 T cell population that expresses cell surface makers of effector/memory cells and produce Th1 and Th2 cytokines immediately upon activation. Unlike conventional CD4 T cells that are selected by thymic epithelial cells, these CD4 T cells, named T-CD4 T cells, are selected by MHC class II expressing thymocytes. Previously, we showed that the presence of T-CD4 T cells protected mice from airway inflammation suggesting an immune regulatory role of T-CD4 T cells. To further understand the function of T-CD4 T cells, we investigated immune responses mediated by T-CD4 T cells during bacterial infection because the generation of antigen specific CD4 T cells contributes to clearance of infection and for the development of immune memory. The current study shows a suppressive effect of T-CD4 T cells on both CD8 and CD4 T cell-mediated immune responses during Listeria and Helicobacter infections. In the mouse model of Listeria monocytogenes infection, T-CD4 T cells resulted in decreasedfrequency of Listeria-specific CD8 T cells and the killing activity of them. Furthermore, mice with T-CD4 T cells developed poor immune memory, demonstrated by reduced expansion of antigen-specific T cells and high bacterial burden upon re-infection. Similarly, the presence of T-CD4 T cells suppressed the generation of antigen-specific CD4 T cells in Helicobacter pylori infected mice. Thus, our studies reveal a novel function of T-CD4 T cells in sup-pressing anti-bacterial immunity.
