The immunoglobulin class of antispermatozoal antibodies in serum.

The aim of this study was to determine the immunoglobulin class of circulating antisperm antibody using a technique called the indirect immunobead test (IBT). In the IBT sperm bound antibodies are detected using polyacrylamide beads coated with rabbit antihuman immunoglobulin classes IgG, IgA, and IgM. Of the 20 infertile men with serum immobilizins, 100% were found to be positive for sperm-bound IgG, 50% positive for IgA, and 0% positive for IgM, using the IBT. Similarly, 20 infertile females with serum immobilizins showed 95% positivity for IgG, 60% for IgA, and 15% for IgM. Thus there was a good correspondence between the presence of serum immobilizins as determined by the sperm immobilization test (SIT) and the IBT. This study provides data that indicates that IgG and IgA are the two major immunoglobulin classes of sperm antibody in male and female immune sera as detected by a simple, sensitive immunological technique, the serum IBT.