Cloning of the immunodominant l7-kDa antigen from Cryptosporidium parvum

Infection with Cryptosporidium parvum causes a self-limiting diarrheal illn ess in immunocompetent humans and is associated with the development of a s erum IgG antibody response dominated by the 27-kDa and 17-kDa parasite surf ace antigens. Antibodies against the 27-kDa and 17-kDa antigens may serve a s useful markers for past infection in population-based studies of the risk factors associated with Cryptosporidium infection. A recombinant form of t he 17-kDa antigen would be useful both in epidemiologic studies and in stud ies of the role of the humoral response in immunity. We have partially puri fied and sequenced the immunodominant 17-kDa surface antigen from sporozoit es, and we have cloned a 975 bp open reading frame from C. parvum that incl udes all of the 17-kDa antigen peptide sequences. We show immunologic ident ity between a recombinant form of the protein and the native 17-kDa antigen . We conclude that the carboxy-terminal fragment of the cloned protein is t he authentic 17-kDa antigen. Published by Elsevier Science B.V.