Estimation of anti-spermatozoa antibody concentrations by a [125I]protein-A binding assay in sera of infertile patients.

A solid-phase radioimmunoassay was developed for measuring the concentration of antispermatozoa antibodies in the sera of sterile patients. Whole human spermatozoa fixed in methanol and immobilized on plastic microtiter plates were used as antigens, and the spermatozoa-bound antibodies were quantitated with the aid of [125I]protein-A. The assay is specific, simple to perform and up to 1000 tests can be carried out conveniently by one technician on a single working day. The new test was shown to correlate better with immunological sterility than the sperm microagglutination and immobilisation tests. An antispermatozoa antibody concentration of 210 micrograms/l and above was found be indicative of an immunological cause of infertility.