Evidence from C57BL/6 mice suggests that CD8+ T cells, specific to the immunodominant HSV-1 glycoprotein B (gB) H-2b–restricted epitope (gB498–505), protect against ocular herpes infection and disease. However, the possible role of CD8+ T cells, specific to HLA-restricted gB epitopes, in protective immunity seen in HSV-1–seropositive asymptomatic (ASYMP) healthy individuals (who have never had clinical herpes) remains to be determined. In this study, we used multiple prediction algorithms to identify 10 potential HLA-A*02:01–restricted CD8+ T cell epitopes from the HSV-1 gB amino acid sequence. Six of these epitopes exhibited high-affinity binding to HLA-A*02:01 molecules. In 10 sequentially studied HLA-A*02:01–positive, HSV-1–seropositive ASYMP individuals, the most frequent, robust, and polyfunctional CD8+ T cell responses, as assessed by a combination of tetramer, IFN-γ-ELISPOT, CFSE proliferation, CD107a/b cytotoxic degranulation, and multiplex cytokine assays, were directed mainly against epitopes gB342–350 and gB561–569. In contrast, in 10 HLA-A*02:01–positive, HSV-1–seropositive symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent clinical herpes disease) frequent, but less robust, CD8+ T cell responses were directed mainly against nonoverlapping epitopes (gB183–191 and gB441–449). ASYMP individuals had a significantly higher proportion of HSV-gB–specific CD8+ T cells expressing CD107a/b degranulation marker and producing effector cytokines IL-2, IFN-γ, and TNF-α than did SYMP individuals. Moreover, immunization of a novel herpes-susceptible HLA-A*02:01 transgenic mouse model with ASYMP epitopes, but not with SYMP epitopes, induced strong CD8+ T cell–dependent protective immunity against ocular herpes infection and disease. These findings should guide the development of a safe and effective T cell–based herpes vaccine.

Key Points miR-17∼92 promotes proliferation and terminal effector differentiation in CD8 T-cells by upregulating PI3K-AKT-mTOR signaling.

The Herpes Simplex Virus type 1 virion tegument phosphoprotein 11/12 (HSV-1 VP11/12) is a major antigen targeted by CD8+ T cells from HSV-seropositive individuals. However, whether and which VP11/12-epitope-specific CD8+ T cells play a role in the “natural” protection seen in seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we used multiple prediction computer-assisted algorithms to identify 10 potential HLA-A*02:01-restricted CD8+ T cell epitopes from the 716 amino acids sequence of VP11/12. Three out of ten epitopes exhibited high to moderate binding affinity to HLA-A*02:01 molecules. In ten sequentially studied HLA-A*02:01 positive and HSV-1-seropositive ASYMP individuals, the most frequent, robust and polyfunctional effector CD8+ T-cell responses, as assessed by a combination of tetramer frequency, granzyme B, granzyme K, perforin, CD107a/b cytotoxic degranulation, IFN-γ and multiplex cytokines assays, were predominantly directed against three epitopes: VP11/1266–74, VP11/12220–228 and VP11/12702–710. Interestingly, ASYMP individuals had significantly higher proportion of CD45RAlowCCR7lowCD44highCD62LlowCD27lowCD28lowCD8+ effector memory T cells (TEM) specific to the three epitopes, compared to symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent ocular herpetic disease). Moreover, immunization of HLA-A*02:01 transgenic mice with the three ASYMP CD8+ TEM cell epitopes induced robust and polyfunctional epitope-specific CD8+ TEM cells that were associated with a strong protective immunity against ocular herpes infection and disease. Our findings outline phenotypic and functional features of protective HSV-specific CD8+ T cells that should guide the development of an effective T-cell-based herpes vaccine.

Herpes simplex virus 1 (HSV-1) glycoprotein B (gB)-specific CD8؉ T cells protect mice from herpes infection and disease. However, whether and which HSV-1 gB-specific CD8؉ T cells play a key role in the "natural" protection seen in HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we have dissected the phenotypes and the functions of HSV-1 gB-specific CD8 O ver a billion individuals worldwide carry herpes simplex virus 1 (HSV-1), which causes a wide range of mild to life-threatening diseases (1-3). Although the virus reactivates from latency and is shed multiple times each year in body fluids (i.e., tears, saliva, and nasal and vaginal secretions), most reactivations are subclinical due to an efficient immune-mediated containment of the infection and disease (4-7). Thus, most infected individuals are asymptomatic (ASYMP) and do not present any apparent recurrent herpetic disease (e.g., cold sores, genital, or ocular herpetic disease). However, a small proportion of individuals experience endless recurrences of herpetic disease, usually multiple times a year, often necessitating continuous antiviral therapy (i.e., with acyclovir and derivatives) (8,9). In those symptomatic (SYMP) individuals, HSV-1 frequently reactivates from latency, reinfects the eyes, and may trigger recurrent and severe corneal herpetic disease, a leading cause of infectious corneal blindness in

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Yersinia pestis, a Gram‐negative bacterium, is the etiological agent of pneumonic and bubonic plague and still active in various regions of the world. Because plague is highly infectious and can readily spread by aerosolization, it poses a bioterrorism threat. The effective induction of mucosal as well as systemic immunity is an important attribute of an improved vaccine for plague. An alternative approach described here is the use of protective epitopes derived from immunodominant antigens (F1 and V) of Yersinia pestis. As T‐cell immunity is also a major contributor of protection, microencapsulated B‐T constructs of F1 and V antigen were used to immunize outbred and inbred mice through intranasal route, and lympho‐proliferative response and cytokine profile of both Th1 and Th2 arms were measured in spleen, lamina propria and Peyer’s patches. Three B‐T constructs of F1 antigen and seven of V antigen showed significantly high T‐cell response in terms of inducing systemic as well as mucosal response when compared to constituent peptides. These ten conjugates showed Th1 cytokine profile whereas rest of the conjugates showed mixed Th1/Th2 response. Four conjugates of V antigen showed high level of IL‐10 production. In present study, microencapsulated B‐T constructs after intranasal immunization generated systemic as well as mucosal immune response in all three sites, which offers an alternative approach for plague vaccine.

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Capsular F1 and secretory V antigen are the putative vaccine candidates for plague, caused by Yersinia pestis. Contemplating this, we studied the immunogenicity and protective efficacy of collinearly synthesized B- and T-cell epitopes (B-T constructs) of V antigen entrapped in poly (DL-lactide-co-glycolide) microparticles immunized intranasally using single dose immunization schedule in outbred, H-2(b) and H-2(d) mice. High antibody levels were observed in terms of IgG, IgA and SIgA peak titers in sera and mucosal washes to different B-T constructs. The constructs ai, bi and fi especially showed high peak antibody titers ranging from 51,200 to 204,000, which were maintained till day 120 post immunization. IgG/IgA Specific activity in sera and washes correlated well with the peak antibody titers. Moreover, all the B-T constructs showed mixed IgG1 and IgG2a/2b response, variable immunoreactivity as well as memory response with V antigen. B-T constructs, viz ai, ak, bi, fi, di and ik showed comparatively high isotype levels. These constructs showed high immunoreactivity, and good recall response with V antigen. Finally, in vivo protective study in BALB/c mice demonstrated the protective efficacy of three B-T constructs (ai, bi and fi) against lethal doses of Yersinia pestis till day 20 post challenge, while construct 'id' showed partial protection.