Immunological approaches to fertility regulation
Stevens, V.C.
Bulletin of the World Health Organization 56(2): 179-192
1978
ISSN/ISBN: 0042-9686 PMID: 307451 Document Number: 407994
In view of strong evidence that there are specific components of the reproductive system that are not represented in other body systems, and that many of these are immunogenic, efforts are being made to develop an acceptable vaccine for fertility regulation. It is hoped that such a vaccine could be administered at infrequent intervals by specially trained technicians in regions without clinics or medical facilities. For safety and practical reasons, an approach using active immunization procedures with a vaccine is preferred to passive immunization with antibodies. In experiments with sperm antigens, immunization with lactate dehydrogenase isoenzyme (LDH-X), 1 of the enzymes normally present on the sperm surface, caused reduced fertility in mice and rabbits; there was, however, significant embryo mortality and further study is required. Other sperm antigens were also tested but most were rejected. Most of the research on ovum antigens was directed towards the zona pellucida, and work is in progress at many centers to isolate experimental quantities of specific zona pellucida antigens. Antibodies to human zona react with pig zona and vice versa thus providing a model system to evaluate such antigens. Antibodies to whole-placenta homogenates disrupt pregnancy in several species of laboratory animal and 2 of the placenta-specific proteins were evaluated as potential antigens, since antibodies to them do not react with any other tissue so far tested. Three protein hormones were isolated from placental tissue and 2 were studied as potential antigens. The problems of testing the safety of possible antigens require extensive study.