Use of fluorescently-labeled MeV in rhesus macaques demonstrated that lymphoid cells, and in particular B cells, are highly susceptible to virus infection (McChesney et al., 1997; de Swart et al., 2007) and that one of the entry receptors for MeV is CD150, also called signaling lymphocyte activation molecule (SLAM). This evidence concerns the gene SLAMF1 and viral infectious disease.