T-CELL ACTIVATION BY SUPERANTIGENS

Superantigens stimulate powerful T-cell responses that can have marked effects in vivo, sometimes leading to shock or even death. The demons tration that strong T-cell responses to superantigens in vivo can be f ollowed by tolerance, reflecting either clonal elimination or anergy, has provided important insights into how mature T cells can be regulat ed. Further progress in understanding the factors that control these r esponses relies heavily on defining the specific interactions between T-cell receptors, superantigens and major histocompatibility complex m olecules which lead to T-cell activation as well as on the characteriz ation of the specific signal transduction events and molecules involve d in this activation. Significant progress has been made, during the p ast year, in the first area and these findings are summarized below; t hough less information is available in the latter area, recent observa tions relevant to this issue are discussed.