title: Absence of corpus luteum rescue by chorionic gonadotropin in women immunized with a contraceptive vaccine.
abstract: OBJECTIVE
  To determine whether antibodies induced by a betahCG vaccine in women are competent to neutralize the luteotropic action of hCG.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Hospitals and a laboratory at an academic center.
  
  
  METHODS
  Six immunized and three control women of reproductive age, participating in a clinical testing of betahCG contraceptive vaccine.
  
  
  METHODS
  Increasing doses of hCG simulating early pregnancy.
  
  
  METHODS
  Anti-hCG antibody titers, serum progesterone and urinary hCG levels, and onset of menses.
  
  
  RESULTS
  Administration of hCG to mimic early pregnancy sustained serum progesterone concentrations and extended the luteal phase in control women. In contrast, serum progesterone levels declined and the luteal phase was not extended if prevailing antibody titers were > or =40 ng/mL in women who had been immunized with a betahCG based vaccine. No booster effect was seen in anti-hCG titers after hCG challenge.
  
  
  CONCLUSIONS
  Antibodies elicited by a betahCG vaccine inactivate hCG and prevent the hormone from rescuing corpus luteum, resulting in progesterone fall and normal menses. Lack of booster in the antibody response confirms the reversibility of the approach.
authors.affiliation: Immunoendocrinology Laboratory, National Institute of Immunology, New Delhi, India.
authors.forename: R
authors.initials: R
authors.lastname: Pal
authors.forename: O
authors.initials: O
authors.lastname: Singh
mesh_terms: D000328:Adult; D000906:Antibodies / Q000032:analysis; D006063:Chorionic Gonadotropin / Q000276:immunology* / Q000652:urine; D003269:Contraception, Immunologic; D003338:Corpus Luteum / Q000502:physiology*; D005260:Female; D006801:Humans; D008183:Luteal Phase; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies; D022642:Vaccines, Contraceptive / Q000494:pharmacology*
chemical_list: D000906:Antibodies; D006063:Chorionic Gonadotropin; D022642:Vaccines, Contraceptive; D011374:Progesterone