H-2-specific T suppressor cells. I. Evidence for T suppressor inducer and effector molecules in suppression

Area of Science:

• Immunology
• Cellular Immunology
• Transplantation Immunology

Background:

• T suppressor (Ts) cells play a critical role in immune regulation by dampening immune responses.
• Understanding the induction and function of antigen-specific Ts cells is crucial for developing immunotherapies.

Purpose of the Study:

• To induce and characterize H-2-specific T suppressor (Ts) cells.
• To investigate the suppressive capacity of these Ts cells on delayed type hypersensitivity (DTH) and mixed lymphocyte responses (MLR).
• To explore the involvement of CD4+ and CD8+ T cells and their secreted molecules in Ts cell-mediated suppression.

Main Methods:

• Induction of H-2-specific Ts cells via intravenous injection of X-irradiated allogeneic spleen cells.
• Assessment of DTH response suppression following adoptive transfer of Ts cells.
• Evaluation of Ts cell-secreted molecules (Tsfi and Tsfe) on MLR.
• Adoptive transfer experiments to assess the presence of memory Ts cells.

Main Results:

• Intravenous injection of X-irradiated C57BL/6 spleen cells successfully induced H-2-specific Ts cells in CBA/J mice.
• These Ts cells significantly suppressed DTH responses (78%) and inhibited MLRs (> 87%) through Tsfi and Tsfe molecules.
• Both CD4+ and CD8+ T cells were implicated in the suppression.
• Secondary immunization led to a higher number of Ts cells, suggesting the development of memory Ts cells.

Conclusions:

• H-2-specific T suppressor cells can be effectively induced and mediate suppression of DTH and MLR.
• CD4+ and CD8+ T cells, along with their secreted factors, are key components of this suppressive mechanism.
• Evidence suggests the existence of memory T suppressor cells, opening avenues for long-term immune tolerance strategies.