Features of effective T Cell-inducing vaccines against Chronic viral infections

Tumorimmunolog

Systematic meta-review of supported self-management for asthma: a healthcare perspective

BACKGROUND: Supported self-management has been recommended by asthma guidelines for three decades; improving current suboptimal implementation will require commitment from professionals, patients and healthcare organisations. The Practical Systematic Review of Self-Management Support (PRISMS) meta-review and Reducing Care Utilisation through Self-management Interventions (RECURSIVE) health economic review were commissioned to provide a systematic overview of supported self-management to inform implementation. We sought to investigate if supported asthma self-management reduces use of healthcare resources and improves asthma control; for which target groups it works; and which components and contextual factors contribute to effectiveness. Finally, we investigated the costs to healthcare services of providing supported self-management. METHODS: We undertook a meta-review (systematic overview) of systematic reviews updated with randomised controlled trials (RCTs) published since the review search dates, and health economic meta-analysis of RCTs. Twelve electronic databases were searched in 2012 (updated in 2015; pre-publication update January 2017) for systematic reviews reporting RCTs (and update RCTs) evaluating supported asthma self-management. We assessed the quality of included studies and undertook a meta-analysis and narrative synthesis. RESULTS: A total of 27 systematic reviews (n = 244 RCTs) and 13 update RCTs revealed that supported self-management can reduce hospitalisations, accident and emergency attendances and unscheduled consultations, and improve markers of control and quality of life for people with asthma across a range of cultural, demographic and healthcare settings. Core components are patient education, provision of an action plan and regular professional review. Self-management is most effective when delivered in the context of proactive long-term condition management. The total cost (n = 24 RCTs) of providing self-management support is offset by a reduction in hospitalisations and accident and emergency visits (standard mean difference 0.13, 95% confidence interval -0.09 to 0.34). CONCLUSIONS: Evidence from a total of 270 RCTs confirms that supported self-management for asthma can reduce unscheduled care and improve asthma control, can be delivered effectively for diverse demographic and cultural groups, is applicable in a broad range of clinical settings, and does not significantly increase total healthcare costs. Informed by this comprehensive synthesis of the literature, clinicians, patient-interest groups, policy-makers and providers of healthcare services should prioritise provision of supported self-management for people with asthma as a core component of routine care. SYSTEMATIC REVIEW REGISTRATION: RECURSIVE: PROSPERO CRD42012002694 ; PRISMS: PROSPERO does not register meta-reviews

Antigen presentation deficiency, mesenchymal differentiation, and resistance to immunotherapy in the murine syngeneic CT2A tumor model

BackgroundThe GL261 and CT2A syngeneic tumor lines are frequently used as immunocompetent orthotopic mouse models of human glioblastoma (huGBM) but demonstrate distinct differences in their responses to immunotherapy.MethodsTo decipher the cell-intrinsic mechanisms that drive immunotherapy resistance in CT2A-luc and to define the aspects of human cancer biology that these lines can best model, we systematically compared their characteristics using whole exome and transcriptome sequencing, and protein analysis through immunohistochemistry, Western blot, flow cytometry, immunopeptidomics, and phosphopeptidomics.ResultsThe transcriptional profiles of GL261-luc2 and CT2A-luc tumors resembled those of some huGBMs, despite neither line sharing the essential genetic or histologic features of huGBM. Both models exhibited striking hypermutation, with clonal hotspot mutations in RAS genes (Kras p.G12C in GL261-luc2 and Nras p.Q61L in CT2A-luc). CT2A-luc distinctly displayed mesenchymal differentiation, upregulated angiogenesis, and multiple defects in antigen presentation machinery (e.g. Tap1 p.Y488C and Psmb8 p.A275P mutations) and interferon response pathways (e.g. copy number losses of loci including IFN genes and reduced phosphorylation of JAK/STAT pathway members). The defect in MHC class I expression could be overcome in CT2A-luc by interferon-γ treatment, which may underlie the modest efficacy of some immunotherapy combinations. Additionally, CT2A-luc demonstrated substantial baseline secretion of the CCL-2, CCL-5, and CCL-22 chemokines, which play important roles as myeloid chemoattractants.ConclusionAlthough the clinical contexts that can be modeled by GL261 and CT2A for huGBM are limited, CT2A may be an informative model of immunotherapy resistance due to its deficits in antigen presentation machinery and interferon response pathways

Enforced OX40 Stimulation Empowers Booster Vaccines to Induce Effective CD4+ and CD8+ T Cell Responses against Mouse Cytomegalovirus Infection

There is an imperative need for effective preventive vaccines against human cytomegalovirus as it poses a significant threat to the immunologically immature, causing congenital disease, and to the immune compromised including transplant recipients. In this study, we examined the efficacy of synthetic long peptides (SLPs) as a CD4(+) and CD8(+) T cell-eliciting preventive vaccine approach against mouse CMV (MCMV) infection. In addition, the use of agonistic OX40 antibodies to enhance vaccine efficacy was explored. Immunocompetent C57BL/6 mice were vaccinated in a prime-boost vaccination regiment with SLPs comprising various MHC class I- and II-restricted peptide epitopes of MCMV-encoded antigens. Enforced OX40 stimulation resulted in superior MCMV-specific CD4(+) as CD8(+) T cell responses when applied during booster SLP vaccination. Vaccination with a mixture of SLPs containing MHC class II epitopes and OX40 agonistic antibodies resulted in a moderate reduction of the viral titers after challenge with lytic MCMV infection. Markedly, the combination of SLP vaccines containing both MHC class I and II epitopes plus OX40 activation during booster vaccination resulted in polyfunctional (i.e., IFN-γ(+), TNF(+), IL-2(+)) CD4(+) and CD8(+) T cell responses that were even higher in magnitude when compared to those induced by the virus, and this resulted in the best containment of virus dissemination. Our results show that the induction of strong T cell responses can be a fundamental component in the design of vaccines against persistent viral infections

Demarcated thresholds of tumor-specific CD8 T cells elicited by MCMV-based vaccine vectors provide robust correlates of protection.

The capacity of cytomegalovirus (CMV) to elicit long-lasting strong T cell responses, and the ability to engineer the genome of this DNA virus positions CMV-based vaccine vectors highly suitable as a cancer vaccine platform. Defined immune thresholds for tumor protection and the factors affecting such thresholds have not well been investigated in cancer immunotherapy. We here determined using CMV as a vaccine platform whether critical thresholds of vaccine-specific T cell responses can be established that relate to tumor protection, and which factors control such thresholds. We generated CMV-based vaccine vectors expressing the E7 epitope and tested these in preclinical models of HPV16-induced cancer. Vaccination was applied via different doses and routes (intraperitoneal (IP), subcutaneous (SC) and intranasal (IN)). The magnitude, kinetics and phenotype of the circulating tumor-specific CD8 Immunization with CMV-based vaccines via the IP or SC route eliciting vaccine-induced CD8 This study highlight the effectiveness of CMV-based vaccine vectors, and shows that demarcated thresholds of vaccine-specific T cells could be defined that correlate to tumor protection. Together, these results may hold importance for cancer vaccine development to achieve high efficacy in vaccine recipients

The Breadth of Synthetic Long Peptide Vaccine-Induced CD8⁺ T Cell Responses Determines the Efficacy against Mouse Cytomegalovirus Infection

<div><p>There is an ultimate need for efficacious vaccines against human cytomegalovirus (HCMV), which causes severe morbidity and mortality among neonates and immunocompromised individuals. In this study we explored synthetic long peptide (SLP) vaccination as a platform modality to protect against mouse CMV (MCMV) infection in preclinical mouse models. In both C57BL/6 and BALB/c mouse strains, prime-booster vaccination with SLPs containing MHC class I restricted epitopes of MCMV resulted in the induction of strong and polyfunctional (i.e., IFN-γ⁺, TNF⁺, IL-2⁺) CD8⁺ T cell responses, equivalent in magnitude to those induced by the virus itself. SLP vaccination initially led to the formation of effector CD8⁺ T cells (KLRG1^hi, CD44^hi, CD127^lo, CD62L^lo), which eventually converted to a mixed central and effector-memory T cell phenotype. Markedly, the magnitude of the SLP vaccine-induced CD8⁺ T cell response was unrelated to the T cell functional avidity but correlated to the naive CD8⁺ T cell precursor frequency of each epitope. Vaccination with single SLPs displayed various levels of long-term protection against acute MCMV infection, but superior protection occurred after vaccination with a combination of SLPs. This finding underlines the importance of the breadth of the vaccine-induced CD8⁺ T cell response. Thus, SLP-based vaccines could be a potential strategy to prevent CMV-associated disease.</p></div

SLP vaccination elicits polyfunctional CD8⁺ T cells.

<p>Following SLP vaccination or MCMV infection the cytokine polyfunctionality of splenic CD8⁺ T cells was determined after peptide restimulation. Representative plots show IFN-γ versus TNF production at <b>(A)</b> day 8 (acute phase) and <b>(B)</b> day 60 (memory phase) post booster vaccination and post MCMV infection. Pie charts depict the percentages of the single (IFN-γ), double (IFN-γ/TNF) and triple (IFN-γ/TNF/IL-2) cytokine producers of each antigen-specific T cell population upon peptide stimulation. Data represents mean values, and are representative of three independent experiments (n = 4–5 per group). Statistics of the results depicted in these pie charts are reported in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005895#ppat.1005895.s005" target="_blank">S4 Fig</a>.</p

Phenotypic heterogeneity of SLP vaccine-induced CD8⁺ T cells.

<p><b>(A)</b> Peripheral blood from either SLP immunized (day 7 after booster peptide vaccination) or MCMV infected C57BL/6 and BALB/c mice (day 7 post infection) were stained with MHC class I tetramers and for cell surface molecules. Representative plots show CD127 versus KLRG1 expression on tetramer-positive CD8⁺ T cells. <b>(B)</b> Cell-surface characteristics of tetramer-positive CD8⁺ T cells in blood and spleen at day 8 post booster SLP vaccination and day 8 after MCMV infection. <b>(C)</b> Peripheral blood from either SLP immunized (day 60 after booster peptide vaccination) or MCMV infected C57BL/6 and BALB/c mice (day 60 post infection) were stained with MHC class I tetramers and for cell surface molecules. Representative plots show CD127 versus KLRG1 expression on tetramer-positive CD8⁺ T cells. <b>(D)</b> Cell-surface characteristics of antigen-specific CD8⁺ T cells in blood and spleen at day 60 post booster SLP vaccination and day 60 after MCMV infection. Data represents mean values, and are representative of three independent experiments (n = 6 per group).</p

Prime-boost SLP vaccination provokes the induction of robust CD8⁺ T cell responses analogous to MCMV infection.

<p><b>(A)</b> The magnitude of the CD8⁺ T cell responses specific to the indicated epitopes was determined in blood by MHC class I tetramer staining at day 7 post booster vaccination with SLPs and at day 7 post MCMV infection in C57BL/6 mice and in BALB/c mice. Representative flow cytometry plots show MHC class I tetramer (Tm) staining within the CD8⁺ T cell population. Numbers represent the percentage of Tm+ cells within the total CD8⁺ T cell population. <b>(B)</b> Longitudinal analysis of the epitope-specific CD8⁺ T cell responses induced by either SLP vaccination or MCMV infection in blood. Data represents mean values ± SEM (n = 6 per group). <b>(C)</b> Percentages and total numbers of splenic SLP and MCMV-specific CD8⁺ T cells during the acute phase (at day 7 post booster vaccination and day 8 and after MCMV infection) and memory phase (at day 60 post booster vaccination and day 60 post MCMV infection) are shown. Data represents mean values + SEM (n = 6 per group), and are representative of three independent experiments. *, P< 0.05; **, P<0.01; ***, P<0.001.</p

Efficacy of single SLP vaccines against acute MCMV infection.

<p>Unvaccinated (naive), SLP vaccinated and MCMV infected C57BL/6 and BALB/c mice were challenged at day 60 post vaccination/infection with 5 × 10⁴ PFU and 5 × 10³ PFU salivary gland-derived MCMV Smith, respectively. At day 5 post challenge, spleen, liver, and lungs were isolated and the viral genome copies were determined by qPCR. The viral titres of individual <b>(A)</b> C57BL/6 and <b>(B)</b> BALB/c mice are depicted (n = 5–8 per group). Mean ± SEM is indicated. Dashed line represents the detection limit as measured in naive mice. Experiments were performed twice with similar outcome. *, P< 0.05; **, P<0.01; ***, P<0.001; ns, not significant.</p