Abstract
Abstract: :
Purpose:We have demonstrated that CD8+ T cells that are present in herpes simplex virus type 1 (HSV-1) latently infected mouse trigeminal ganglia (TG) can block HSV-1 reactivation from latency, at least in part through the production of interferon gamma (IFN-g). Here we define the epitope specificity of these CD8+ T cells. Methods:At 14 and 34 days after corneal infection with the RE strain of HSV-1, the latently infected TG were removed, digested with collagenase, and the phenotype and function of CD8+ T cells in the TG cell suspension was determined by flow cytometry. The cells were stained for CD8, HSV-1 glycoprotein B (gB [aa 498-505]) tetramer, or HSV-1 ribonucleotide reductase (RR1 [aa 822-829]) tetramer, and/or intracellular IFN-g. Staining was performed on CD8 cells freshly isolated from the TG or following 5 hours of stimulation with syngeneic epithelial cells that were uninfected, HSV-1 infected, gB peptide pulsed, or RR1 peptide pulsed. Results:CD8 T cells in day 14 TG: 11% produced IFN-g in response to HSV-1 infected targets, 14% produced IFN-g in response to gB peptide pulsed targets, 0% produced IFN-g in response to RR1 peptide pulsed targets, 56% were stained with gB tetramers, and 2 % were stained with RR1 tetramers. CD8 T cells in day 34 TG: 45% produced IFN-g in response to HSV-1 infected targets, 48% produced IFN-g in response to gB peptide pulsed targets, 0% produced IFN-g in response to RR1 peptide pulsed targets, 54% were stained with gB tetramers, and 0 % were stained with RR1 tetramers Conclusion:Approximately 50% of the CD8 T cells in HSV-1 latently infected ganglia are HSV-1 specific, and all of these are specific for the immunodominant gB peptide. 20% of HSV-specific CD8 T cells in day 14 TG but all of those in day 34 TG produced IFN-g. The CD8+ T cells that prevent HSV-1 reactivation in mouse TG appear to be stimulated by an HSV-1 gB peptide.
Keywords: 425 herpes simplex virus • 469 microbial pathogenesis: experimental studies • 435 immunomodulation/immunoregulation