Immunologic analysis of sperm-immobilizing factor found in sera of women with unexplained sterility

Abstract

It has long been postulated that human female infertility might be due to an antisperm antibody. Several methods were used to detect the antisperm antibody in the serum of sterile women and it was demonstrated that the sperm immobilization test was the best procedure. Three of 25 women with unexplained sterility showed a positive sperm immobilization test. The sperm-immobilizing factor in patient's serum which gave the strongest positive test was analyzed immunologically. This factor, which was present in the γ-globulin fraction of serum, was not dialyzable. It displayed activity only with complement and was specifically absorbed only by spermatozoa. After absorption to spermatozoa, it was eluted by heat. 131I-labeled γ-globulin from the patient, absorbed onto sperm and eluted with heat, localized more than twice as much on re-exposure to sperm than did absorbed and eluted 131I-γ-globulin from normal subjects.