Human T and B cell immunoreactivity to a recombinant 23-kDa Cryptosporidium parvum antigen

Cryptosporidial infection in humans results in parasite-specific IgG, IgM, and IgA antibody responses, but little is known of the cell-mediated immune responses to cryptosporidial antigens. In a convenience sample of 35 Haiti an residents, there was a high level of cryptosporidial exposure (> 90%) as determined by immunoblot reactivity of serum against cryptosporidial antig ens. An attempt was made to determine if there was a relationship between a ntibody and T cell-mediated responses to recombinant Cp23 antigen and how t his correlated with reactivity to crude sporozoite antigen preparations (SA g). T cell reactivity was greater against SAg (57%) than to Cp23 (34.3%) as measured by [H-3]thymidine incorporation. Proliferative responses to Cp23 were significantly correlated with SAg responses. By enzyme-linked immunoso rbent assay, most persons had IgG responses to both SAg (91.4%) and to reco mbinant Cp23 (88.5%). Antibody responses were greater among persons who exh ibited T cell responses to SAg and Cp23. This study demonstrates that recom binant Cp23 antigen could be a useful antigen for detection of both antibod y and cell-mediated responses in epidemiologic studies.