Antigenic complementarity between HIV and other AIDS-associated infections results in idiotype-antiidiotype antibody complexes that cross react with lymphocyte proteins.

HIV proteins mimic HLA proteins, and the proteins of cofactor infections (cytomegalovirus, hepatitis viruses, mycobacteria, mycoplasmas) mimic CD4 proteins, making some HIV antigens molecularly complementary to cofactor antigens. Antibodies to HIV and its cofactors should therefore act like idiotype-antiidiotype pairs. Over 2000 combinations of antibodies were tested for such complementarity using modified forms of Ouchterlony immunodiffusion and ELISA. HIV antibodies do precipitate some antibodies against cofactor infections including CMV, HBV, mycobacteria and mycoplasmas. These antibodies also mimic antibodies against HLA and CD4 proteins. Thus, some combinations of HIV with cofactor infections may induce lymphocytotoxic antibodies (LCTA), a risk that must be addressed in vaccine development.