Abstract:

Objective To explore the mechanism of down-regulation of regulatory T cells（Treg） by immunization with attenuated activated autologous T cells. Methods Autologous T cells were activated with ConA in vitro. Mice were immunized subcutaneously and intraperitoneally every 5 days for 3 times (5×10⁶ per time for each mouse), and the number and function of Treg were examined. PBS was subcutaneously injected for control group. Serum level of anti-mouse CD25 antibody was measured by ELISA. The number and function of Treg was detected by serum adoptive transfer and proliferation and inhibition assays. Results Compared with control group, there were less CD4⁺CD25⁺Foxp3⁺ Treg in the mice after immunization (P<0.01), the immunosuppression ability decreased (P<0.01), and the level of anti-CD25 antibody increased (P<0.01). Adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice (P<0.01). Conclusion Immunization with attenuated activated autologous T cells induces more anti-CD25 antibody, which may further down-regulate CD4⁺CD25⁺Foxp3⁺ Treg expansion and function in vivo.

Key words: autologous T cell, regulatory T cell, CD4, CD25, Foxp3, antibody, mouse