[Antifertility effect of an active immunization of monkeys with human pregnancy-specific beta 1-glycoprotein (SP1) (author's transl)].

Fertile female cynomolgus monkeys (Macaca fascicularis) were actively immunized against human pregnancy-specific beta 1-glycoprotein (SP1). Native SP1 as well as chemically modified derivatives of SP1 served as antigens. The effect of the immunization on reproduction in these animals was investigated. The immunized monkeys showed a significant reduction in fertility: the conception rate in these animals was only slightly reduced when compared with the controls; but in the immunized monkeys pregnancy often resulted in abortion. The possibility of using immunization against SP1 as a contraceptive method in man is discussed.