ATTEMPTS TO PROTECT SEVERE COMBINED IMMUNODEFICIENT (SCID) MICE WITH ANTIBODY ENRICHED FOR REACTIVITY TO CRYPTOSPORIDIUM-PARVUM SURFACE ANTIGEN-1

Cryprosporidium parvum is a protozoal pathogen which infects the gastr ointestinal epithelium of mammals causing diarrhoea, the duration and severity of which is determined by the immunocompetency of the host, C urrently, there is no effective treatment or prevention, We evaluated the ability of surface antigen-1 (SA-1), defined as those antigens rec ognized by neutralizing mAb 17.41, to elicit a protective antibody res ponse when used as an immunogen, A SA-1 enriched fraction was obtained by immunoaffinity chromatography and was used to immunize a naive Hol stein calf. SA-l immune serum from this calf detected C, parvum epitop es to a 1:10 000 dilution in a dot blot assay, and sporozoite surface epitopes at a 1:10 000 dilution in a live immunofluorescence assay. We stern blot analysis showed that SA-1 immune bovine serum recognized a similar pattern of C. parvum antigens as the defining mAb 17.41, Oral passive transfer of SA-1 immune bovine serum did not protect severe co mbined immunodeficient (scid) mice or suckling BALE /c mice from initi al infection with C, parvum, or terminate a persistent infection in sc id mice.