APOPTOSIS AS A CAUSE OF T-CELL UNRESPONSIVENESS IN EXPERIMENTAL CHAGAS-DISEASE

A murine model of Chagas' disease induced by metacyclic forms of T. cr uzi was used to evaluate T-cell function during infection. T-cell unre sponsiveness to TcR;CD3 stimulation in vitro and lymphocyte activation in vivo occurred simultaneously. These paradoxical findings are discu ssed in the light of recent evidence that mature activated T cells bec ome susceptible to TcR-mediated apoptosis. Activation-induced death in T cells from T. cruzi-infected mice has recently been demonstrated in this model. Evidence that TcR-induced death of activated T cells coul d be a cause for T-cell unresponsiveness in vitro and in vivo, as well as the possible molecular mechanisms involved, are discussed.