Endogenous production of VEGF₁₆₅ by MDDCs correlates with reduced HTLV-1 entry. (A) Effect of endogenous VEGF₁₆₅ production by MDDCs on receptor expression or HTLV-1 binding. (Left panels) Cell-surface expression of HSPGs, NRP-1, and GLUT-1 on nonproducing (LPS stimulation) and VEGF₁₆₅-producing (LPS + PGE₂ stimulation) MDDCs, determined by flow cytometry. (Right panels) Nonproducing and VEGF₁₆₅-producing MDDCs were incubated with either HTLV-1 SU or HTLV-1 virions (black lines) or control SU-ASLV-rFc or medium (gray lines) and the amount of binding determined. (B) Effect of endogenous VEGF₁₆₅ production by MDDCs on the internalization of HTLV-1 or HIV-1 virus. Nonproducing (top panels) and VEGF₁₆₅-producing (bottom panels) MDDCs were incubated with culture medium (gray lines), and 25 ng/mL (low), 50 ng/mL (medium), or 100 ng/mL (high) HIV-1 (black lines) or with culture medium (gray line) or 100 ng/mL HTLV-1 (black line) and the amount of internalization was determined. (C) Effect of endogenous VEGF₁₆₅ production by MDDCs on HTLV-1 or HIV-1 infection. MDDCs were infected with 100 ng of either HTLV-1 or HIV-1 virions. Seven days later, supernatants from individual wells were collected (8 wells/condition), and MDDC infection was measured by quantifying the concentration in supernatants of the viral core protein, MAp19 for HTLV-1 (left histogram) or CAp24 for HIV-1 (right histogram). The data are the mean ± SD of 1 representative experiment of 3 performed in octuplicate.