Respiratory syncytial virus infection and the tight junctions of nasal epithelial cells.

Respiratory syncytial virus (RSV) primarily infects upper respiratory tract cells, mainly nasal epithelial cells. The tight junctions of nasal epithelial cells are thought to perform important innate immune function against foreign materials including respiratory viruses. We investigated in vitro the relationship of RSV infection and the tight junctions of primary nasal epithelial cells which had been transfected with human telomerase reverse transcriptase (hTERT) to prolong cell life. Nasal epithelial cells developed tight junctions when cultured in medium containing fetal bovine serum, and these cells showed apparent resistance to RSV infection compared to control cells. RSV could infect these cells from apical but not basolateral side, suggesting that only apical side possess RSV receptor or a mechanism for absorbing RSV particles. Importantly, RSV infection of the cells enhanced the expression of tight junction proteins occludin, claudin-4 and ZO-1. These findings suggest that RSV infection induces polarity in the infected cells. This polarity could facilitate cellular secretion of propagated RSV, thereby spreading the infection.