Specific IgA antibody response to coproantigens of Cryptosporidium parvum in serum and saliva of calves after experimental infection

The antibody response to coproantigens of Cryptosporidium pan urn was exami ned in saliva and sera of calves experimentally infected with C, parvum. Co proantigens of C, parvum? with approximate molecular masses of 17, 15 and l ess than 14 kDa were found in the feces of infected calves on day 3 or late r, and 60 and 23 kDa coproantigens observed between days 4 and 9 post-infec tion, respectively. The antibody reactivity to the coproantigens was mainly attributable to IgA class antibodies in saliva and was detectable during t he convalescent phase of infection. A 15 kDa protein isolated from the fece s of infected calves by immunoaffinity adsorption using a monoclonal anti C , parvum antibody was recognized by IgA antibodies present in the saliva du ring the convalescent phase of infection. These results suggest that this c oproantigen may be released from C. parvum sporozoites and may induce IgA a ntibody production in the mucosal immune system of infected calves, (C) 200 1 Elsevier Science B,V. All rights reserved.