Antigen-specific regulatory T cells eliminate cognate CD4 effector T cells through perforin, granzyme B, and Bim.
T cells (Tregs) maintain immune tolerance, yet how they selectively eliminate cognate CD4+ effector T cells remains unclear. We propose a co-activation-dependent elimination mechanism, conceptually akin to synthetic lethality. Using in vitro co-cultures, we show that simultaneous peptide-MHC II recognition by Tregs and...