ERVW-1 and infection: By confirming and extending our prior finding that Vpr-mediated stabilization of Env promotes macrophage to T cell spread (Collins et al., 2015) we also provide an explanation for how Vpr increases infection of human lymphoid tissue ex vivo (Eckstein et al., 2001; Rucker et al., 2004), which contain macrophages and T cells in a highly physiological, three-dimensional environment.