These data reveal the existence of two subsets of M-CSF-derived MDM; a small subset of Siglec-1hiCD4+CD163+MDM (non-adherent), with a relatively high expression of molecules that are associated with HIV-1 infection, and a more prominent subset of Siglec-1LoCD4−CD163−MDM (adherent), with a relatively lower expression of Siglec-1, and devoid of CD4 and CD163. Here, CD4 is linked to HIV-1 infection.