Infection of differentiated airway epithelial cells from caprine lungs by viruses of the bovine respiratory disease complex

Bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus type 3 (BPIV3) and bovine herpesvirus type 1 (BHV-1) are important pathogens associated with the bovine respiratory disease complex (BRDC). Non-bovine ruminants such as goats may also be infected and serve as a virus reservoir to be considered in the development of control strategies. To evaluate the susceptibility of caprine airway epithelial cells to infection by viruses of BRDC, we established a culture system for differentiated caprine epithelial cells. For this purpose, we generated precision-cut lung slices (PCLS), in which cells are retained in their original structural configuration and remain viable for more than a week. The three bovine viruses were found to preferentially infect different cell types. Ciliated epithelial cells were the major target cells of BPIV3, whereas BHV-1 preferred basal cells. Cells infected by BRSV were detected in submucosal cell layers. This spectrum of susceptible cells is the same as that reported recently for infected bovine PCLS. While infection of caprine cells by BRSV and BPIV3 was as efficient as that reported for bovine cells, infection of caprine cells by BHV-1 required a tenfold higher dose of infectious virus as compared to infection of bovine airway cells. These results support the notion that non-bovine ruminants may serve as a reservoir for viruses of BRDC and introduce a culture system to analyze virus infection of differentiated airway epithelial cells from the caprine lung.