Although limited by the fact that only F-MuLV-, but not SFFV-infected cells are readily detected after infection with our FV-mWasabi complex, our target cell analysis reveals a dynamic pattern of FV-mWasabi-infected cells over the course of infection and shows that follicular B and CD4+ T cells indeed contribute to the chronic FV load, although macrophages carry the bulk of chronic FV. This evidence concerns the gene CD4 and infection.