Detection of species-specific and cross-reactive epitopes in Sarcocystis cystozoites by monoclonal antibodies.

A total of 24 hybridoma cell lines producing monoclonal antibodies (mAbs) to Sarcocystis muris were established from 3 fusions performed on mice that had been immunized with total protein derived from cystozoites. In all, 19 mAbs were of the IgG1 isotype, 3 were of the IgG2a isotype, and 2 were of the IgG3 isotype. The reactivity of the mAbs with homologous and heterologous antigens was examined by an indirect fluorescent antibody test, an enzyme-linked immunosorbent assay (ELISA), and a dot ELISA. MAbs were directed against various structures of the cystozoite as revealed by different immunofluorescence patterns. In all, 12 mAbs recognized only antigens of S. muris cystozoites, whereas the other 12 mAbs also recognized various antigens of cystozoites of S. gigantea, S. tenella, S. arieticanis, S. capracanis, S. miescheriana, or S. suihominis. No cross-reactions with endozoites of Toxoplasma gondii were observed.