Abstract: | An enzyme-linked immunosorbent assay (ELISA) was adapted for the horse to investigate the production of antibody in response to subcutaneous, intrauterine or intravaginal immunization with dinitro-phenylated human serum albumin. An IgM response was not detected, but antibodies of the IgGab, IgGc, IgGT and IgA isotypes were measured in serum, uterine and vaginal secretions. Local immunization produced antibody titres in serum and secretions, with evidence of significant local production. |