Zona pellucida antibodies in human sera.

A quantitative indirect immunofluorescent assay developed for the measurement of antibodies produced in rabbits against porcine zonae pellucidae was modified and used to detect autoantibodies specific to human zonae pellucidae. An undetermined number of human serum constituents which appear to vary quantitatively between individuals had the capacity to bind non-specifically the porcine zonae used as antigen in this assay. Binding was reduced or eliminated by altering the chemical composition of the assay system until the only positive results were for sera from infertile, sub-fertile and menopausal women. These positive sera were adsorbed with washed porcine blood cells, spleen cells, and liver cells. Each tissue completely removed the positive binding to porcine zonae. The positive sera were also tested against human oocytes with and without porcine tissue adsorption, and no positive fluorescence was detected. It is therefore unlikely that the antibodies in human sera which bind to porcine zonae pellucidae could be a causal factor in infertility in women.