CD4 and infection: Ephrins have an important role in inflammatory (Dixit et al., 1990; Ivanov & Romanovsky, 2006) and immune response to infection (Darling & Lamb, 2019; Funk & Orr, 2013), including CD8 and CD4 T cell migration (Saintigny et al., 2012), and further have been shown to regulate endothelial (Chan & Sukhatme, 2009) and lung vascular permeability during injury (Larson et al., 2008).