R Pal1, O Singh. 1. Immunoendocrinology Laboratory, National Institute of Immunology, New Delhi, India.
Abstract
OBJECTIVE: To determine whether antibodies induced by a betahCG vaccine in women are competent to neutralize the luteotropic action of hCG. DESIGN: Prospective clinical study. SETTING: Hospitals and a laboratory at an academic center. PATIENT(S): Six immunized and three control women of reproductive age, participating in a clinical testing of betahCG contraceptive vaccine. INTERVENTION(S): Increasing doses of hCG simulating early pregnancy. MAIN OUTCOME MEASURE(S): Anti-hCG antibody titers, serum progesterone and urinary hCG levels, and onset of menses. RESULT(S): 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. CONCLUSION(S): 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.
OBJECTIVE: To determine whether antibodies induced by a betahCG vaccine in women are competent to neutralize the luteotropic action of hCG. DESIGN: Prospective clinical study. SETTING: Hospitals and a laboratory at an academic center. PATIENT(S): Six immunized and three control women of reproductive age, participating in a clinical testing of betahCG contraceptive vaccine. INTERVENTION(S): Increasing doses of hCG simulating early pregnancy. MAIN OUTCOME MEASURE(S): Anti-hCG antibody titers, serum progesterone and urinary hCG levels, and onset of menses. RESULT(S): 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. CONCLUSION(S): 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.