Induction of HIV-1 release from sequestration in epithelial cells.

<p>(A) Polarized tonsil epithelial cells containing HIV-1_SF33 for 6 days were treated with ionomycin (10 μM), cytochalasin D (12 μg/ml), or a combination of ionomycin and cytochalasin D for 30 min. Intracellular virus and virus released from AP and BL medium were examined by ELISA p24 (upper panel) and TER was measured in control and treated cells (lower panel). Mean values ± SEM of three independent experiments (in triplicate or quadruplicate) are shown (n = 3). *P < 0.01 and **P < 0.002, BL virus release of ionomycin+cytochalasin D-treated cells compared with BL virus release of cells treated independently with ionomycin or cytochalasin D. (B, C) Polarized tonsil epithelial cells containing sequestered R5-tropic HIV-1_SF170 (B) and X4-tropic HIV-1_92UG029 (C) at day 6 were treated with ionomycin or a combination of ionomycin and cytochalasin D for 30 min. TER of polarized cells was measured in control and treated cells. Combined AP and BL medium and trypsinized cells were examined for released and intracellular virus, respectively. Mean values ± SEM of three independent experiments (in triplicate) are shown (n = 3). ***<i>P</i> < 0.0001, virus release from cells treated with ionomycin+cytochalasin D compared with ionomycin alone. (D) Polarized tonsil epithelial cells containing sequestered HIV-1_SF33 at day 6 were treated with ionomycin for 30 min or untreated. Activated CD4+ T lymphocytes were infected with culture medium collected from untreated and ionomycin-treated cells. After 10 days, CD4+ T lymphocytes were examined for HIV-1 infection by using ELISA p24. Results were reproduced in three independent experiments and are shown as mean ± SEM (n = 3). # Not detected.