The effect of Nef expression during HIV-1 infection in MDMs. (A) MDMs (2 × 10⁵/well) of 2 donors were infected either with wild-type HIV-1_NF462 or HIV-1_NF462dNef. The supernatants of these wells were harvested at 3- or 4-day intervals after infection, and viral production was monitored by sequential quantitation of p24 by ELISA. (B) The CBA kit was used to measure the level of chemokines (MIP-1α and MIP-1β) in cell supernatants 14 days after HIV infection.