In agreement with IFN-I resistance of cell-to-cell infection of macrophages, IFNα-induction of APOBEC3G and 3A, Mx2, and likely other IFN-induced factors such as the Vpu-counteracted Bst-2/tetherin protein, does not affect macrophage infection by cell-cell fusion. The gene discussed is IFNA1; the disease is infection.