RESUMO
The antibody response to coproantigens of Cryptosporidium parvum was examined in saliva and sera of calves experimentally infected with C. parvum. Coproantigens of C. parvum with approximate molecular masses of 17, 15 and less than 14kDa were found in the feces of infected calves on day 3 or later, and 60 and 23kDa coproantigens observed between days 4 and 9 post-infection, respectively. The antibody reactivity to the coproantigens was mainly attributable to IgA class antibodies in saliva and was detectable during the convalescent phase of infection. A 15kDa protein isolated from the feces of infected calves by immunoaffinity adsorption using a monoclonal anti C. parvum antibody was recognized by IgA antibodies present in the saliva during the convalescent phase of infection. These results suggest that this coproantigen may be released from C. parvum sporozoites and may induce IgA antibody production in the mucosal immune system of infected calves.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/imunologia , Doenças dos Bovinos/imunologia , Criptosporidiose/veterinária , Cryptosporidium parvum/imunologia , Imunoglobulina A/biossíntese , Saliva/imunologia , Animais , Anticorpos Monoclonais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Western Blotting/veterinária , Bovinos , Doenças dos Bovinos/parasitologia , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Eletroforese em Gel de Poliacrilamida , Fezes/parasitologia , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/análise , Imunoglobulina G/sangue , Masculino , Saliva/parasitologiaRESUMO
Antibodies against Cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. Salivary anti-C. parvum IgA antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. Salivary anti-C. parvum IgG antibody levels showed a gradual increase along with the change in IgA antibody levels during the infection. In contrast, serum anti-C. parvum IgA antibody levels showed only a slight increase between days 15 and 30 post-challenge. Serum anti-C. parvum IgG antibody levels rose on day 12 post-challenge and one calf maintained relatively high level up to the end of the experiment. In immunoblotting, an antigen with a molecular mass of 15 kDa was found to react strongly to salivary IgA antibody and a 27 kDa antigen to react to serum IgG antibody.