TREATMENT OF OOCYTES AND IN VITRO FERTILIZED EMBRYOS WITH MONOCLONAL ANTIBODIES AND GUINEA PIG COMPLEMENT FOR NEUTRALIZATION OF CONTAMINATING BOVINE HERPESVIRUS-1

The association of bovine herpesvirus-1 (BHV-1) with oocytes and in vitro fertilized (IVF) embryos after treatment with a mixture of three BHV-1 monoclonal antibodies (AB) and guinea pig complement (GPC) was investigated in a series of three experiments. Exposure of cumulus-oocyte complexes (COC) to BHV-1 (10(5) TCID50/ml) in the maturation medium for 22 h followed by treatment with the AB alone or with a mixture of AB and GPC prior to fertilization, yielded a total of 15% of resulting embryos free of the virus. When the cumulus-free oocytes/zygotes were treated with a mixture of AB and GPC after fertilization and then co-cultured in the medium containing bovine oviductal epithelial cells (BOEC), 88% of samples containing embryos (n = 70) were free of the virus. Application of the same treatment or GPC alone followed by the culture of zygotes in the medium without BOEC yielded all 40 samples containing 123 embryos free of the infectious virus. In addition, the Day-7 embryos exposed to BHV-1 and then treated with a mixture of AB and GPC were tested negative. In conclusion, these experiments suggest that BHV-1 contamination of zygotes and Day-7 IVF embryos may be neutralized by treatment with a mixture of AB and GPC or GPC alone. The results also show that it is advantageous to use the IVF embryo culture system free of supporting cells in order to increase the number of embryos free from the infectious virus.