Antigen-specific regulatory T cells eliminate cognate CD4 effector T cells through perforin, granzyme B, and Bim.

Cognate antigen recognition enables antigen-specific Tregs to eliminate CD4 effector T cells via perforin, granzyme B, and Bim, revealing a precise cytotoxic mechanism.

• Why it matters: Understanding how Tregs selectively target effector T cells is crucial for developing therapies for autoimmune diseases, allergies, and cancer, yet the molecular details remain unclear.
• What they did: The study used in vitro co-cultures and an airway inflammation model to demonstrate that Tregs require dual peptide-MHC II activation to induce apoptosis in responder T cells, involving perforin, granzyme B, and Bim.
• The result: Findings show that Treg-mediated cytotoxicity depends on specific molecular pathways, enabling targeted immune regulation and informing potential therapeutic strategies across various immune-related conditions.