Immunoconjugates to increase photoinactivation of bovine alphaherpesvirus 1 in semen.

Artificial insemination and in vitro embryo production are increasingly used to improve the reproductive efficiency of herds, however success of these techniques depends on the sanitary quality of the semen. Insemination centers commonly use antibiotics in their routine procedure, but they are not able against viruses. In this paper, we demonstrate a new approach for disinfecting virus in bovine semen using photoimmunoinactivation, an adaptation of the photodynamic inactivation (PDI) methodology. The photosensitizers (PSs), hematoporphyrin (HP) and zinc tetracarboxy-phthalocyanine (ZnPc) were conjugated to Immunoglobulin Y (IgY) anti-bovine alphaherpesvirus 1 (BoHV-1) and used for PDI against the BoHV-1 viruses in cell culture and compared to the unconjugated PSs. Both treatments proved to be efficient, but a significant decrease in the irradiation time required to completely eliminate the virus was observed in the samples treated with the immunoconjugates. Photophysical measurements help us to understand the coupling between PSs and IgY and the evaluated production of singlet oxygen. Following the cell culture test, the same approach was applied in semen artificially infected with BoHV-1. The immunoconjugates were also efficient for complete virus inactivation up to 5 min of irradiation and proved to be safe using several parameters of sperm viability, demonstrating the feasibility of our strategy for disinfection viruses in semen.