AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY (ELISA) FOR THE DETECTION OF ANTISPERM ANTIBODIES IN HORSE SERUM

An enzyme-linked immunosorbent assay (ELISA) was developed and evaluat ed to detect equine antisperm antibodies (ASA) in horse serum. Six mai den mares between 12 and 18 mo of age were immunized with stallion spe rm cells (SC group, n=2), seminal plasma (SP group, n=2), or phosphate -buffered saline (PBS) as a control (C group, n=2). Horses received a second injection of the same antigen 2 wk after the first. Blood was c ollected weekly for 10 wk after initial immunization and again at Week 15. Serum ASA levels (IgG and IgA) were measured by ELISA using two a ssay systems, one containing stallion SC as the plate antigen and anot her containing SP. In horses immunized with SC, peak IgG levels were d etected by ELISA during Wk 2 and 3 after first injection using either plate antigen. The antibody levels persisted through Week 5 and then s lowly declined until Week 15. Horses immunized with SP had IgG levels that did not differ from control horses using either ELISA plate antig en. The only significant elevation in serum IgA ASA occured during Wee k 5 after initial immunization and only in mares immunized with SC as detected by ELISA using SC as the plate antigen. Attachment of ASA to stallion spermatozoa was confirmed by an indirect immunofluorescence a ssay.