Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have pre...Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.展开更多
Objective: To evaluate the role of regulatory T cells (Tregs) at late stages of stroke. Methods:Anti-CD25 antibody (or PBS as a control) was injected to reduce the pool of Tregs in Wistar rats;then, ischemia was induc...Objective: To evaluate the role of regulatory T cells (Tregs) at late stages of stroke. Methods:Anti-CD25 antibody (or PBS as a control) was injected to reduce the pool of Tregs in Wistar rats;then, ischemia was induced transiently by middle cerebral artery occlusion during 60 min and reperfusion was allowed for 7 d. Then, Treg frequency was analyzed in peripheral blood, spleen and lymph nodes. Neurological score (0-6) and infarct volume were also determined. Results: Nine days after injection, the CD4+CD25+ T cells were reduced by 70.4%, 44.8% and 57.9% in peripheral blood, spleen and lymph nodes, respectively compared to PBS-treated rats. In contrast, the reduction of CD4+FOXP3+ T cells was lower in the same compartments (38.6%, 12.5%, and 29.5%, respectively). The strongest reduction of CD25+CD4+ T cells was observed in those FOXP3-negative cells in blood, spleen and lymph nodes (77.8%, 52.8%, and 60.7%, respectively), most likely corresponding to activated T cells. Anti-CD25-treated transient middle cerebral artery occlusion rats had a lower neurological deficit and did not develop tissue damage compared with PBS-treated animals. Conclusions: These findings suggest that treatment with anti-CD25 in our model preferentially reduce the T cell population with an activated phenotype, rather than the Treg population, leading to neuroprotection by suppressing the pathogenic response of effector T cells.展开更多
基金This work was supported by National Natural Science Foundation of China(No.30671945)Science and Technology Commission of Shanghai Municipality(Nos.06JC14044,05ZR14055,054319928,04DZ14902)+2 种基金Shanghai Municipal Education(No.05BZ26)Shanghai Leading Academic Discipline Project(T0206)Science Foundation of Shanghai Institute of Immunology(No.07-A04,to Ningli Li).
文摘Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.
文摘Objective: To evaluate the role of regulatory T cells (Tregs) at late stages of stroke. Methods:Anti-CD25 antibody (or PBS as a control) was injected to reduce the pool of Tregs in Wistar rats;then, ischemia was induced transiently by middle cerebral artery occlusion during 60 min and reperfusion was allowed for 7 d. Then, Treg frequency was analyzed in peripheral blood, spleen and lymph nodes. Neurological score (0-6) and infarct volume were also determined. Results: Nine days after injection, the CD4+CD25+ T cells were reduced by 70.4%, 44.8% and 57.9% in peripheral blood, spleen and lymph nodes, respectively compared to PBS-treated rats. In contrast, the reduction of CD4+FOXP3+ T cells was lower in the same compartments (38.6%, 12.5%, and 29.5%, respectively). The strongest reduction of CD25+CD4+ T cells was observed in those FOXP3-negative cells in blood, spleen and lymph nodes (77.8%, 52.8%, and 60.7%, respectively), most likely corresponding to activated T cells. Anti-CD25-treated transient middle cerebral artery occlusion rats had a lower neurological deficit and did not develop tissue damage compared with PBS-treated animals. Conclusions: These findings suggest that treatment with anti-CD25 in our model preferentially reduce the T cell population with an activated phenotype, rather than the Treg population, leading to neuroprotection by suppressing the pathogenic response of effector T cells.
