The virus with full length Env has higher specific infectivity than virus with truncated Env, and is capable to establish productive infection in permissive T cells and persistent infection in non-permissive cells such as epithelial and dendritic cells or macrophages [49,50] because early steps in replication appear to be more efficient in viruses having a long cytoplasmic tail incorporated into lipid rafts domains of incoming particles (Fig. 7A, B). The gene discussed is ERVW-1; the disease is infection.