HSV-2 infection compromises the ability of immature DCs to stimulate SIV-specific responses. Immature moDCs from SHIV162P-infected macaques were infected with HSV-2 (5 pfu per cell) (HSV) or not (Med) before being recultured for 4 hours in the presence (+) or absence (–) of AT-2 SIV E11S (30 ng p27 per 105 DCs). The DCs were collected and viable cells recounted and plated in triplicate at varying doses with 5 × 104 to 2 × 105 autologous T cells. IFN-γ responses were monitored by ELISPOT (A-C) and other soluble factors measured in the supernatants using the Luminex assay (D). (A) The mean (± SEM) numbers of SIV-specific spot-forming cells (SFC) per 2 × 105 cells are plotted. The background levels of IFN-γ release in the absence of AT-2 SIV (0 SFCs for the medium-treated DC–T cell and 14 SFCs for the HSV-2–infected DC–T cell mixtures) have been subtracted to show the SIV-specific responses. Results from a representative animal are provided. (B) Representative PHA responses induced by the differently treated DC preparations (5 × 104 T cells with 2.5 × 103 DCs) are illustrated (mean ± SEM). Low-level SIV-specific responses (that are lowest in the HSV-2–infected DC cultures) are still apparent (compare the “+” versus “–” AT-2 SIV for Med- and HSV-treated DCs). (C) The fold reduction in the SIV-specific IFN-γ release for each experiment was calculated by dividing the mean SIV-specific IFN-γ release induced by medium-treated DCs by the mean SIV-specific IFN-γ release induced by HSV-treated DCs. The fold reduction in the IFN-γ release in the presence of PHA for each experiment was calculated by dividing the mean PHA-driven IFN-γ responses induced by medium-treated DCs by the mean responses induced by HSV-treated DCs. The mean fold lower (± SEM) SIV-specific (5 animals) and PHA-induced (3 animals) responses stimulated by HSV-2–infected DCs are shown. The values for the responses induced by medium-treated DCs are 1. (D) The pg/mL of TNF-α, CCL3, and CCL5 are graphed for cultures of 5 × 104 T cells with 2.5 × 103 DCs. PHA-induced TNF-α, CCL3, and CCL5 responses were also lower in cultures stimulated with HSV-2–infected DCs (16.19 versus 80.66, 18.78 versus 66.64, and 81.98 versus 123.84 pg/mL for infected versus uninfected DC-stimulated cultures, respectively). Data are shown from 1 representative experiment of 3 performed (3 different macaque donors).
