title: Use of synthetic peptides as immunogens for developing a vaccine against human chorionic gonadotropin.
abstract: Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the placental trophoblast soon after conception and is essential for successful gestation in women. A vaccine against this hormone has been developed for the purposes of birth control and the treatment of hormone-related diseases. Synthetic peptides representing the native primary structure of the hCG beta subunit have been coupled to protein carriers to produce immunogens. Several peptides, representing varying lengths from the C-terminus of the beta subunit, were synthesized and their ability to elicit antibodies reactive to hCG and able to neutralize hCG activity in vivo was tested. A peptide representing the 37 amino acids of the C-terminal end of the beta subunit was selected as the vaccine antigen and diphtheria toxoid was selected as the carrier for the first prototype vaccine. Procedures for coupling a specified number of peptide molecules to each carrier molecule in a reproducible fashion were developed. The immunogen is mixed with an adjuvant compound and the mixture administered in an oil-in-water emulsion. Significant levels of antibodies to hCG have been elicited in several species and a marked reduction in the fertility of immunized baboons has been observed. Extensive evaluations of vaccine safety have been conducted and Phase I clinical trials have been proposed to test its utility for human birth control. Possible applications of the hCG vaccine to health problems other than birth control are being considered.
mesh_terms: D000276:Adjuvants, Immunologic; D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens / Q000008:administration & dosage; D006063:Chorionic Gonadotropin / Q000276:immunology*; D003269:Contraception, Immunologic; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007114:Immunization; D010215:Papio; D010446:Peptide Fragments / Q000276:immunology; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology*; D014612:Vaccines / Q000008:administration & dosage / Q000302:isolation & purification*
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D006063:Chorionic Gonadotropin; D000939:Epitopes; D010446:Peptide Fragments; D010455:Peptides; D014612:Vaccines