Increased expression of PDGF-BB in pulmonary endothelial cells on treatment with HIV-proteins. Representative western blot showing PDGF-BB expression in cellular extracts from Tat (25 ng/ml), gp-120LAV (100 ng/ml), gp-120CM (100 ng/ml), heat-inactivated (HI) Tat or HI-gp-120 treated human pulmonary microvascular endothelial cells. The blots were re-probed with human β-actin antibodies. Histogram represents the average densitometric ratio of PDGF-BB to β-actin of three independent experiments. Statistical significance was calculated using a two-tail, independent t-test. (** p ≤ 0.01 vs. control, #p ≤ 0.05 vs. Tat or gp-120 treatment).