Differences between the discriminatory activity of antisera raised against the total gonadotropins and the Pr-β-hCG-TT for neutralization of hCG and LH action

Abstract

The effect of antibodies from four monkeys immunized with the vaccine Pr-β-hCG-TT has been investigated on LH/hCG induced progesterone synthesis by goat granulosa cells in culture. The antisera in all cases blocked the hCG induced steroidogenesis. In three out of the four cases, the antibodies did not interfere in the oLH action. One antiserum inhibited, partially but not fully, the oLH stimulated progesterone synthesis. On the other hand, antisera raised against the entire gonadotropins (hCG or oLH) neutralized without discrimination the hCG and LH stimulated progesterone synthesis in these cells. The association constants (Ka) of monkey anti-oLH antibodies for binding with hCG and hLH were of the same order (3.3×10¹¹and 8.3×10⁹L/M for hCG and 3.1×10¹¹, 5.2×10¹⁰ & 1.4×10⁹L/M for hLH). K_a of anti-Pr-β-hCG-TT sera for hCG were higher than for hLH.