Gene expression and in vitro replication of bovine gammaherpesvirus type 4.

In vitro cell cultures are widely used models for dissecting cellular and molecular mechanisms that lead to certain physiological conditions and diseases. The pathogenesis of BoHV-4 in the bovine reproductive tract has been studied by conducting tests on primary cultures. However, many questions remain to be answered about the role of BoHV-4 in endometrial cells. The aim of this study was to compare the replication and gene expression of BoHV-4 in cell lines and bovine reproductive tract primary cells as an in vitro model for the study of this virus. We demonstrated that BoHV-4 strains differ in their in vitro growth kinetics and gene expression but have the same cell type preference. Our results demonstrate that BoHV-4 replicates preferentially in bovine endometrial cells (BEC). However, its replication capacity extends to various cell types, since all cells that were tested were permissive to BoHV-4 infection. The highest virus titers were obtained in BEC cells. Nevertheless, virus replication efficiency could not be fully predicted from the mRNA expression profiles. This implies that there are multiple cell-type-dependent factors and strain properties that determine the level of BoHV-4 replication. The results of this study provide relevant information about the in vitro behavior of two field isolates of BoHV-4 in different cell cultures. These findings may be useful for the design of future in vitro experiments to obtain reliable results not only about the pathogenic role of BoHV-4 in the bovine female reproductive tract but also in the development of efficient antiviral strategies.