Treatment of Oocytes and in vitro Fertilized Embryos with Monoclonal Antibodies and Guinea Pig Complement for Neutralization of Contaminating Bovine Herpesvirus‐1

Abstract

ContentsThe association of bovine herpesvirus-I (BHV-I) with oocytes and in vifuo fertilized (IVF) embryos after treatment with a mixture of three BHV-I monoclonal antibodies (AH) and guinea pig complement (GPC) was investigated in a series of three experiments. Exposure of cumulus-oocyte complexcs (COC) to BHV-I (lo5 TCID5,: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 mixturc 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-I 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 ordcr to increase the number of embryos free from the infectious virus. Inhalt Behandlung yon Oozyten und in vitro befruchteten Embryonen rnit monoklonalen Antikorpern und Komplement von Meerschweinchen zur Neutralisation von kontaminiertem Rinder Herpesvirus-1In einer Experimentalreihe wurde der EinfluD von bovinem Herpesvirus -1 (BHV-1) auf Oocyten und in vitro produzierte Embryonen nach Behandlung mit einer Mischung aus drei BHV-1 monoklonoalen Antikorpern (AB) und Meerschweinchen Komplement (GPC) untersucht. Einc Exposition der Kumulus-Oozyten-Komplexe (COC) = mit BHV-I ( lo5 TCID,,/ml) im Reifungsmedium fur 22 Stunden und anschlieBendcr Behandlung rnit AB alleine oder in einer Mischung aus AB und GPC vor der Befruchtung fiihrte bei 15% der spateren Embryonen ZU kcinem Virusiiachweis. Wurden dagegen Kumuluszell-freie OocyteniZygoten einer Mischung aus AB und GPC nach der Befruchtung ausgesetzt und anschlieDend in einem Medium mit boviiicn Eileiter-Epithelzellen (BOEC) kultiviert, so waren 88% der Kulturen rnit 70 Embryonen virusfrei. Anwendung der gleichen Behandlung oder nur rnit GPC und anschlieoender Kultur im Epithelzellfreien Medium fuhrte in 40 Testschalen rnit 123 Embryonen in keinem Fall zur Virusinfektion. AuDcrdem wurden Tag 7Embryonen BHV-I Wren ausgesetzt und rnit AB und GPC behandelt. Alle Testergebnisse waren negativ. Es wird hieraus gefolgert, daB eine BHV-I Virusinfektion von Zygoten und Tag 7 Embryoneii mit einer Mischbehandlung aus AB und GPC bzw. nur rnit GPC neutralisiert werden kann. Die Ergebnisse zeigen auch, daR es vorteilhaft sein kann, TVF-Kultursysteme zu verwenden, die frei von Helferzellen sind, um die Zahl virusfreier Embryoncn zu erhohcn.

Evaluation of Trypsin Treatment on the Inactivation of Bovine Herpesvirus Type 1 on In Vitro Produced Pre‐implantation Embryos

“…In vitro bovine embryos are at risk for contamination with BoHV-1. This can occur via infected oocytes and spermatozoa or from contaminated products of animal origin that are used in media for in vitro embryo production (Bielanski and Dubuc 1994;Eaglesome and Garcia 1997;Bielanski et al 1998;Wrathall et al 2006). The aim of this study was to evaluate the efficiency of trypsin treatment on the inactivation of BoHV-1 in experimentally infected bovine embryos produced by in vitro fertilization.…”

“…In vitro bovine embryos are at risk for contamination with BoHV‐1. This can occur via infected oocytes and spermatozoa or from contaminated products of animal origin that are used in media for in vitro embryo production (Bielanski and Dubuc 1994; Eaglesome and Garcia 1997; Bielanski et al. 1998; Wrathall et al.…”

Embryo transfer, a potential risk in disease transmission

“…This procedure yielded 88% of the embryos free of the virus whereas all the controls were positive. 26 Antibodies could also be present in animal products used during ET procedures as well as during the in vitro production of embryos. Although this may be an inconvenience in the detection of positively infected samples by serological status, it may be advantageous due to the potential in inactivating pathogens.…”