Wild-type measles virus induces large syncytium formation in primary human small airway epithelial cells by a SLAM(CD150)-independent mechanism

In the natural course of measles virus (MV) infection, epithelial cells are primary targets of MV. However, it has been shown that wild-type MV utilizes signaling lymphocyte activation molecule (SLAM or CD150) as a cellular receptor, which is expressed only in some T and B cells, thymocytes, and dendritic cells. To understand how wild-type MV infects non-lymphoid cells, several non-lymphoid cells were examined for their susceptibility to wild-type MV. Here, we show that wild-type MV can infect primary human small airway epithelial cells (SAEC) and induce formation of large syncytia in vitro. mRNA specific for SLAM was not detected in SAEC, indicating that wild-type MV infects SAEC and induces syncytia formation via a SLAM-independent mechanism.