The role of superantigens in infectious diseases Exogenous antigens are presented to T lymphocytes through a mechanism that ensures a high recognition specificity. On the other hand, recently described superantigens are particles that do not follow the processing or presentation route and do not bind to a specific region of T lymphocyte receptors, as conventional antigens. These particles bind to a large number of T lymphocytes, generating a disproportionate and unspecific immune response. Two types of superantigens have been described. Endogenous superantigens, that are transported in the host genoma, and that are involved in clonal depletion and immunological tolerance phenomena. Exogenous superantigens, mostly bacterial toxins, are involved in several diseases. There is evidence that these antigens participate in diseases such as Kawasaki disease, toxic shock caused by Staphylococcus aureus, rheumatoid arthritis, HIV infection and Streptococcus pyogenes infections