Molecular mimicry: a critical look at exemplary instances in human diseases.

Molecular mimicry, the concept that antigenic determinants of microorganisms resemble antigenic determinants of the host, is frequently cited as a plausible mechanism to account for the association of infection and autoimmune disease. Based on analogous sequences of amino acids or on cross-reactions of monoclonal antibodies, numerous examples of such mimicry have been reported. There are, however, no clear examples of a human disease caused by molecular mimicry.