NGF does not influence HIV-I cDNA synthesis and integration. Macrophages were infected by an R5-tropic HIV-1 isolate (Ba-L) and treated with NGF (10 ng/mL) for 24 hours. Total DNA was then extracted using the QIAamp DNA kit and PCRs were performed directly toward the 2 LTR segments (LTR-LTR) (A) and to LTR and Alu sequences (LTR-Alu) (B). The left panel displays a representative gel with the PCR products for both targets (LTR-LTR and LTR-Alu) in HIV-1–infected cells treated or not with NGF. The numbers shown in this panel represent the number of cells from which total DNA was extracted and used as the template for PCR amplifications. The right panel shows the band densitometry from 4 independent experiments (mean ± SEM). Absolute quantification of provirus DNA was performed by qPCR assays normalized by serial 10-fold dilution of the ACH-2 cell line (C). Bars represent means ± SEM of 2 independent experiments run in triplicate.