Supernatants from HIV-1IIIB THP-1 infected cells and HIV-1Ba-L infected MDM induce neuritic retraction in human DRG neurons. Confocal images of anti-βIII tubulin immunostained DRG cultures treated for 24 hours with supernatants from uninfected THP-1 cells (A, 1:10 dilution; C, 1:100 dilution), HIV-1IIIB (B, 1:10 dilution; D, 1:100 dilution), uninfected MDM (E, 1:10 dilution; G, 1:100 dilution) and HIV-1Ba-L supernatant (F, 1:10 dilution; H, 1:100 dilution). (I) Reduction of the total neuritic length per axon is shown as standardized data. * Supernatant from infected monocytic cells versus the matched control, p < 0.05.