FIGURE 7.
A proposed model of phenotypic and functional characteristics of HSV-specific CD8+ T cells in HSV-seropositive SYMP versus ASYMP individuals. After stimulation with HSV-1 ASYMP epitopes, CD8+ T cells (purple) from HSV-seropositive ASYMP individuals develop more protective CD8+ T cells that prevent herpes disease. In contrast, after stimulation with HSV-1 SYMP epitopes, CD8+ T cells (orange) from SYMP individuals develop more pathogenic CD8+ T cells that lead to inflammation. CD8+ T cells from SYMP individuals secrete substantial amounts of proinflammatory cytokines IL-6, IL-8, and IL-17 (small red circles) and have low proliferation and low lytic granules. In contrast, CD8+ T cells from ASYMP individuals have efficient proliferation and clonal expansion, and they produce more lytic granules and more IL-2, IFN-γ, and TNF-α (small blue circles), resulting in decreased or subclinical disease. In SYMP individuals, lower amounts of lytic granules likely account for inefficient killing of HSV-infected target cells.
