Enzyme linked immuno-sorbent assay for detection of antibody activity in female genital tract of immunized rabbits.

A method to assay anti-HCG activity was developed. Polystyrene micro-ELISA plates were coated with HCG and uterine and tubal washings were incubated in the wells. Sera were diluted to equate the protein content with that in the washings and were included in the assay to serve as internal reference standards. Anti-rabbit-IgG (sheep) conjugated to horse-radish peroxidase was added to each well and enzyme activity was monitored using ortho-phenyl-diamine as chromogen agent. Enzyme activity was a direct measure of anti-HCG activity. This method was used to compare anti-HCG activity in the genital tract fluid of rabbits immunized with HCG with that of serum from the same animal. The results of the present study show that at equal protein concentrations, the anti-HCG activity was only 2.64% to 18.73% of the activity present in serum. Thus, it seems that antibody activity in the genital tract of the female rabbits immunized systemically may not be sufficient enough to neutralize the biological function of the antigen needs for contraceptive protection.