Isolation of a human spermatozoal hapten "II2.2' and its reaction with naturally occurring human sperm-immobilizing sera from infertile patients.

An extract of human spermatozoa was prepared using Hyamine 2389 and Triton X-100. With gel and ion-exchange chromatography several fractions were obtained of which are reacted specifically with sperm-immobilizing antibodies of infertile females and males in an immune inhibition test. This fraction showed haptenic properties, ahd a molecular weight of 1600 and was excluded as an anticomplement factor. After conjugation with cytochrome c the hapten II2.2 formed precipitation reactions with 3 out of 4 sperm-immobilizing sera. The titer reduction in sperm-immobilizing sera after adsorption with II2.2 may represent an in vitro model for a possible treatment of infertility in cases of a humoral sensitization against spermatozoa. On the other hand, the hapten might easily be synthesized and could, after conjugation to an appropriate carrier, serve as a contraceptive vaccine.