SUPERANTIGENS - A PARTICULAR INTERACTION BETWEEN MICROORGANISMS AND THE IMMUNE-SYSTEM

The discovery of the superantigens (SAgs) offered new insights on the interaction between microorganisms and the host immune system. Associa ted to Major Histocompatibility Complex (MHC) class II molecules, SAgs bind to the variable domain of the beta chain (V beta) of the TCR alp ha beta engaged in the family specificity of lymphocytes. Therefore, t hese molecules are able to activate a high number of T lymphocytes as well as surface MHC class II bearing cells, leading to an overriding r elease of cytokines and inflammatory mediators, which have been relate d to their toxic effects. Endogenous SAgs are encoded by murine tumor proviruses (Mtv) which are integrated in the genome of mice. Bacteria and viruses produce exogenous SAgs and those related to food poisoning have been widely studied. The presence of parasite SAgs is still uncl ear and further studies are required to establish their existence and effects on the corresponding infections.