CSF2 and HIV-1 infection: In vitro GM-CSF-treatment may enable hCD4/R5/cT1 mouse myeloid-lineage cells to support in vitro HIV-1 infection at almost 25% of the levels observed after infection of primary human monocyte/macrophages by stimulating the production of multivesicular bodies, a well-described site for Gag assembly and HIV-1 budding from infected cells [47] and thereby circumventing the plasma-membrane-associated blocks that compromise Gag processing and T cell infection.