IDENTIFICATION OF CRYPTOSPORIDIUM-PARVUM OOCYST SPOROZOITE ANTIGENS RECOGNIZED BY INFECTED AND HYPERIMMUNE LAMBS

The appearance, persistence and eventual decline of IgG, IgM and IgA a ntibodies recognizing Cryptosporidium parvum antigens were studied in naturally infected lambs using a Western blot technique, and the resul ts compared with those obtained using sera from immunized lambs. There was an intense recognition of some low molecular weight proteins (15- 17 kDa by IgG and IgA; 28-30 kDa by IgA, IgM and IgG) during the infec tion and early post-infection period. These peptides were not recogniz ed after Days 45-60 of life. Some high molecular weight antigens (94 k Da) were weakly recognized on Day 15 but more intensely recognized fro m Day 30 onwards, persisting until at least Day 90. Antibody recogniti on of these C parvum proteins could be an indicator of recent or past exposure to the parasite.