Ovotransferrin expression and release by chicken cell lines infected with Marek's disease virus

Mammals posses both serum transferrin and lactoferrin, whose functions are taken over in birds by ovotransferrin, displaying both iron transport and antibacterial activities, Ovotransferrin also exerts antiviral activity towards Marek's disease virus, an avian member of the herpes famiJy of viruses, This virus infects Iymphoid organs and induces the transcription of ovotransferrin in infected chicken embryo fibroblasts. However, it has not yet been established whether ovotransferrin gene transcription is Iinked to the release or the protein outside the cells or whether ovotransferrin expression and release also occurs in chicken lymphoblastoid cclls in which the Marek 's disease virai genome is integrated. Our results indicate that both serum and egg-white isoforms of ovotransferrin are expressed and released in the supernatants of chicken embryo fibroblast and Iymphoblastoid cells in tbe absence of infection. ViraI infection of chicken embryo fibroblasts caused a slight increase of ovotransferrin release, whereas viraJ reinfection of lyrnphoblastoid cells caused a rernarkable ovotransferrin release in a virus coucentratìon-dependent manner. These findings suggest rhat ovotransferrin release in vivo may play a cruciaJ role in protecting the whole organism from virai infection spreading, and support the hypothesis that the antiviral activity of ovotransferrin is an important part of the innate immune response in birds, resembling the anriviral activity of lactoferrin in marnmals.