HIV tat/gp120-disrupted epithelial junctions facilitate HSV-1 cell-to-cell spread through junctional areas of polarized oral epithelial cells.

<p><b>A.</b> Polarized tonsil cells were treated with active or inactive tat/gp120 and HIV virions for 5 days. Disrupted cells were infected with HSV-1 at 0.01 PFU per cell from basolateral membranes of polarized cells. After 3 days, cells were fixed and immunostained using goat anti-HSV immune serum (green). Cell nuclei are stained in red. Yellow represents colocalization of HSV proteins and nuclei. <b>B.</b> (upper panel) Plaque numbers were counted from 3 independent filter inserts and data are presented as the average number of HSV-infected plaques per insert. (lower panel) Cell-to-cell spread of HSV-1 was quantitatively evaluated by counting HSV-infected cells in the plaques. Results are presented as the average number of HSV-infected cells per plaque. Error bars indicate SEM. <b>C.</b> Polarized cells were infected with HSV-1. After 4 h, antibodies to nectin-1 and gD were added separately and in combination. Cell medium was changed daily to add fresh antibodies. Cells were fixed and immunostained for HSV-1, and the plaque numbers (upper panel) and the number of HSV-1-positive cells in plaques were counted (lower panel). Error bars indicate SEM. *P<0.05, *P<0.01, **P<0.001, all compared with the control group.