Etiology of immune infertility.

Semen of mammalian species contains a built-in system to prevent immunologic sensitization of females against antigens of sperm and seminal plasma in spite of repeated coitus. This prevention of sensitization is likely to be due to the presence of a potent immune response inhibitor originating from one of the sex accessory glands of the male. The inhibitor has been only biologically characterized so far. Failure of this built-in system in the male results in immune response to seminal antigens in the female. This seminal immunity, when of the right kind and magnitude, results in clinical immune-fertility.