An in vitro method using bovine granulosa cells for assaying the neutralising capacity of antibodies to pregnant mare's serum gonadotrophin

Abstract

Superovulatory stimulation of cattle with PMSG causes a second wave of ovarian follicular development (Saeed et al., 1989) accompanied by high concentration of oestradiol in peripheral blood (Alfuraiji et al., 1990) due to its long half life. This effect of PMSG is thought to create an unfavourable steroid environment for early embryonic development. Antibodies to PMSG (APMSG) can be used to remove PMSG from the peripheral blood of PMSG-stimulated cattle after the initial multiple follicular development and rise of oestradiol, and hence, to increases the number of transferable embryos. It has been shown that APMSG neutralises the effect of PMSG and increase the number of transferable embryos when administered relative to the preovulatory LH surge in PMSG-stimulated cattle (Alfuraiji et al., 1993). The beneficial effect of APMSG can not be realised in practice, however, because detection of the preovulatory LH surge is difficult. Therefore, using APMSG in a PMSG superovulation procedure requires further investigation to understand the mode of action of APMSG. The latter could be studied in vitro in a much more controllable way than in vivo. Furthermore, an in vitro method would allow us to test the neutralising capacity of different antibody preparations to PMSG.