Primary macrophages from different donors produce variable levels of HIV; however, the mechanisms are unclear. We tested whether variations in cell-surface or cell-cycle characteristics influenced HIV production. We found that greater basal proliferation of the macrophages prior to infection resulted in more arrested in G2M 3 days post-infection (r2=0.7, P<0.04). Likewise, the number of G2M-arrested macrophages correlated with p24 production (r2=0.78, P<0.02) and apoptosis (r2=0.67, P<0.05) later in the infection. Serum-starvation or reduction, which limit HIV spread, reduced G2M arrest and HIV amounts. Surprisingly, the amount of HIV produced correlated with expression levels of the costimulating ligand, CD86, but not with other important molecules, including class II, CD40, or CD54 (r2=0.96, P<0.0005). These data establish donor characteristics related to variable HIV production in vitro and suggest that altered expression of costimulatory ligands may influence HIV production in vivo.