Recognition of carbohydrate antigen epitopes by sperm-immobilizing antibodies in sera of infertile women

To study carbohydrate natures in the antigen epitopes corresponding to sperm-immobilizing antibodies in infertile women. Antibody absorption with human sperm and seminal plasma before and after treatments with trifluoromethanesulfonic acid or sodium metaperiodate. Thirty-three patients who showed a positive sperm immobilization test provided their sera for the experiment. In 25 patients’ sera whose sperm-immobilizing antibodies were absorbed with human seminal plasma, the antibody absorbing capabilities were completely abolished by deglycosylation treatment with trifluoromethanesulfonic acid. The sperm-immobilizing antibodies in 4 patients’ sera were absorbed out with sperm membrane fraction before the treatment but not after the treatment with trifluoromethanesulfonic acid. In some patients’ sera, the antibody-absorbing capabilities of ejaculated sperm were markedly reduced by sodium metaperiodate treatment. The majority of sperm-immobilizing antibodies in infertile patients might be generated to carbohydrate structures of the sperm-coating antigens or sperm membrane antigens.