We began this exploration by measuring the levels of dUMP present in proviral DNA under three distinct conditions (i) MC that were infected with HIV-1BaL immediately after isolation and then maintained as undifferentiated monocytes for 7 days by culturing under nonadherent conditions in the absence of M-CSF, (ii) MDM infected at the monocyte stage and then allowed to differentiate in the presence of M-CSF (Early Infection, MDMEI) and, (iii) MDM that were infected after seven days of differentiation in M-CSF (Late Infection, MDMLI) (Fig 3A). This evidence concerns the gene CSF1 and infection.