SUPERANTIGENS

Abstract

Superantigens are bacterial, viral, retroviral and some naturally occurring proteins that can specifically activate a large proportion of T and/or B cells. In contrast to classical peptide antigen recognition, superantigens do not require processing to small peptides. T-cell superantigens interact with the immune system by binding to major histocompatibility complex (MHC) class II proteins outside the classical antigen binding groove and activate T cells through the variable region of the T cell receptor beta-chain. B-cell superantigens target B cells, which have restricted usage of variable heavy and light chain and by binding to immunoglobulins outside the conventional antigen binding site, stimulate a high frequency of B cells. Studies of T-cell and B-cell superantigens are important since they are involved in many human diseases and represent a great tool in unravelling some of the basic mechanisms of immune response.