Enzyme-linked immunosorbent determination of autoantibodies to zona pellucida as a possible cause of infertility in women

An enzyme-linked immunosorbent assay (ELISA) for determination of antibodies against the zona pellucida was developed and compared with the already available indirect immunofluorescence (IIF) technique. Sera from 100 women with explained and unexplained infertility were screened for the presence of autoantibodies to the zona pellucida by ELISA and IIF techniques. Porcine/goat zonae immobilized on activated microtitre plates or solubilized zona pellucida antigens adsorbed on poly-L-lysine-coated microtitre plates were used as a solid phase in an ELISA. Assay of anti-zona pellucida antibodies in xenogeneic and allogeneic sera was performed by incubation of test samples with the solid phase against human serum supplied by WHO as a reference positive control, followed by incubation with staphylococcal protein A conjugated to horseradish peroxidase. The ELISA was effectively used to screen the production of monoclonal antibodies from mouse myeloma X mouse splenocyte hybridomas. The sensitivity of the ELISA was more than 2500-fold greater than that of the IIF technique. Significantly high titres of autoantibodies to zona pellucida were found in patients with unexplained infertility as compared with patients with a known cause of infertility, and their normal counterparts.