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

Abstract

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.

PIP: Fertile female cynomolgus monkeys (Macaca fasciculoris) were actively immunized against human pregnancy-specific beta-1-glycoprotein. SP 1 preparations isolated from human placentas and from chemically modified derivatives were used as antigens. After 6 weeks of immunications the monkeys were mated and checked for the effects of the immunizations of their reproductive capacity. Of 16 immunized monkeys, 44% conceived after the 1st mating, compared with 51% of the 39 control group monkeys. All but 3 pregnancies in the immunized monkeys terminated in abortion. Repeated matings of the immunized monkeys resulted in 22 pregnancies and 11 abortions. Monkeys immunized with human SP 1 show a significant reduction in fertility due to the abortive effect of the drug. An immunization of humans against SP 1 might be an important contraceptive technique, if early termination of pregnancy could be guaranteed and barring any negative side effects.