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Clinical and Experimental Immunology. 1978 Aug; 33(2):360-375.Since guidelines for safety evaluation of antifertility vaccines do not exist, this WHO report attempts to define the parameters to be examined and the methodology which might be used for such a safety assessment. In principle, antifertility vaccines may: 1) prevent sperm transport and/or fertilization; 2) prevent or disrupt implantation; and 3) prevent blastocyst development. Potential advantages of this immunological approach to fertility regulation include: 1) possibility of infrequent administration, possibly by paramedicals; 2) use of antigens or antigen frangments that are not pharmacologically active; and 3) the possibility of large-scale synthesis and manufacture of vaccine at relatively low cost in the case of antigens of known chemical structure. To evaluate the efficacy and safety of placental antigen vaccines, placental antigens used should not possess significant immunological similarity with tissue other than placenta. Carriers or haptens may require structural remodifications of placental molecules to overcome natural immunological tolerance. Adjuvants may be needed to enhance the immune response required. Quality-control procedures for vaccine component production include tests for: 1) purity; 2) toxicity; 3) sterility; and 4) shelf-life. Acute, subacute, and chronic toxicity testing in animals is described for it must be performed separately for the haptenated antigen or conjugate and adjuvant. Such tests would include hematological parameters, blood chemistry, urinanaylsis, gross pathological and organ weight analysis, and ophthalmological tests. Animal models are suggested. Means of monitoring the immune reponse and potential hazards of immunization (e.g., allergy or autoimmune disease) are discussed. The rationale and protocol for safety and efficacy studies of human chorionic gonadotropin-peptide vaccine receive similar attention, with emphasis on tests to be performed before human clinical trials can start.
Bulletin of the World Health Organization. 1978; 56(2):179-192.Strong evidence that specific immunogenic components of the reproductive system exist that are not represented in other body systems has led to efforts to develop an acceptable vaccine for fertility regulation. The aim is to create a vaccine administered infrequently by trained technicians outside the clinical environment. For safety and practical reasons, an approach using active immunization with a vaccine is preferred to passive immunization with antibodies. In current research with sperm antigens, a lactate dehydrogenase isoenzyme (LDH-X), an enzyme normally present on the sperm surface, reduced fertility in mice and rabbits. However, significant embryo mortality occurred. Other sperm antigens have been tested and rejected. Most of the research on ovum antigens is directed toward the zona pellucida, and work is in progress to isolate experimental quantities of specific zona pellucida antigens. Antibodies to human zona are reported to react with pig zona and vice versa, providing a model system. Antibodies to whole-placenta homogenates reportedly disrupt pregnancy in several laboratory animal species, and 2 placenta-specific proteins are potential antigens since antibodies to them do not react with any other tissue so far tested. Of 3 protein hormones isolated from placental tissue, 2 are potential antigens. The possible hazards of antifertility vaccines can be divided into 2 categories: problems related to immunization and problems caused by antibodies produced.
Acta Paediatrica Scandinavica. 1978 September; 67(5):553-582.6 research articles plus an introduction constitute this review of present knowledge of lactation and its effects. The superiority of human milk as compared with milk of other origin for feeding newborns, term or preterm, was analyzed in terms of biological development related to digestive, metabolic, and excretory functions during fetal and postnatal life in the 1st article. WHO, concerned with the declining breast feeding rate in developing countries, has organized investigations in 9 different countries of different aspects of breast feeding and breast milk with the aim of formulating programs of intervention. Basic epidemiological data on 24,000 mother/child pairs have just been reported in a preliminary manner, emphasizing socioeconomic differences. The 3rd study investigated the nitrogen and protein components of human milk; the true protein content of human milk is .9% in both well-nourished and malnourished mothers. The next study reviewed lipid and trace element composition of human milk in relation to ethnic variables. Contaminants in human milk are characterized in the next review, with DDT and PCBs the most outstanding. The final article emphasizes new knowledge in human milk immunoglobulin, the most predominant of which is secretory IgA.