Metabolic Phenotypes of Response to Vaccination in Humans.

Herpes zoster (shingles) causes significant morbidity in immune compromised hosts and older adults. Whereas a vaccine is available for prevention of shingles, its efficacy declines with age. To help to understand the mechanisms driving vaccinal responses, we constructed a multiscale, multifactorial response network (MMRN) of immunity in healthy young and older adults immunized with the live attenuated shingles vaccine Zostavax. Vaccination induces robust antigen-specific antibody, plasmablasts, and CD4+ T cells yet limited CD8+ T cell and antiviral responses. The MMRN reveals striking associations between orthogonal datasets, such as transcriptomic and metabolomics signatures, cell populations, and cytokine levels, and identifies immune and metabolic correlates of vaccine immunity. Networks associated with inositol phosphate, glycerophospholipids, and sterol metabolism are tightly coupled with immunity. Critically, the sterol regulatory binding protein 1 and its targets are key integrators of antibody and T follicular cell responses. Our approach is broadly applicable to study human immunity and can help to identify predictors of efficacy as well as mechanisms controlling immunity to vaccination.

Veteran Beliefs About the Causes of Gulf War Illness and Expectations for Improvement.

BACKGROUND: Individuals' beliefs about the etiology of persistent physical symptoms (PPS) are linked to differences in coping style. However, it is unclear which attributions are related to greater expectations for improvement. METHOD AND RESULTS: A cross-sectional regression analysis (N = 262) indicated that Veterans with Gulf War Illness (GWI) who attributed their GWI to behavior, (e.g., diet and exercise), had greater expectations for improvement (p = .001) than those who attributed their GWI to deployment, physical, or psychological causes (p values > .05). CONCLUSIONS: Findings support the possible clinical utility of exploring perceived contributing factors of PPS, which may increase perceptions that improvement of PPS is possible. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02161133.

Characterization of Virus-specific Immune Response During Varicella Zoster Virus Encephalitis in a Young Adult.

An immunocompetent adult received corticosteroids for chest pain, which later was clinically found to be herpes zoster (HZ). She developed severe disease and rapid viral dissemination that elicited an exceptionally strong varicella zoster virus-specific B-cell and CD8 T-cell response. Clinicians should consider atypical HZ presentation prior to corticosteroid administration.

Breadth and Functionality of Varicella-Zoster Virus Glycoprotein-Specific Antibodies Identified after Zostavax Vaccination in Humans.

Herpes zoster (HZ) (shingles) is the clinical manifestation of varicella-zoster virus (VZV) reactivation. HZ typically develops as people age, due to decreased cell-mediated immunity. However, the importance of antibodies for immunity against HZ prevention remains to be understood. The goal of this study was to examine the breadth and functionality of VZV-specific antibodies after vaccination with a live attenuated HZ vaccine (Zostavax). Direct enumeration of VZV-specific antibody-secreting cells (ASCs) via enzyme-linked immunosorbent spot assay (ELISPOT assay) showed that Zostavax can induce both IgG and IgA ASCs 7 days after vaccination but not IgM ASCs. The VZV-specific ASCs range from 33 to 55% of the total IgG ASCs. Twenty-five human VZV-specific monoclonal antibodies (MAbs) were cloned and characterized from single-cell-sorted ASCs of five subjects (>60 years old) who received Zostavax. These MAbs had an average of ∼20 somatic hypermutations per VH gene, similar to those seen after seasonal influenza vaccination. Fifteen of the 25 MAbs were gE specific, whereas the remaining MAbs were gB, gH, or gI specific. The most potent neutralizing antibodies were gH specific and were also able to inhibit cell-to-cell spread of the virus in vitro Most gE-specific MAbs were able to neutralize VZV, but they required the presence of complement and were unable to block cell-to-cell spread. These data indicate that Zostavax induces a memory B cell recall response characterized by anti-gE > anti-gI > anti-gB > anti-gH antibodies. While antibodies to gH could be involved in limiting the spread of VZV upon reactivation, the contribution of anti-gE antibodies toward protective immunity after Zostavax needs further evaluation.IMPORTANCE Varicella-zoster virus (VZV) is the causative agent of chickenpox and shingles. Following infection with VZV, the virus becomes latent and resides in nerve cells. Age-related declines in immunity/immunosuppression can result in reactivation of this latent virus, causing shingles. It has been shown that waning T cell immunity correlates with an increased incidence of VZV reactivation. Interestingly, serum with high levels of VZV-specific antibodies (VariZIG; IV immunoglobulin) has been administered to high-risk populations, e.g., immunocompromised children, newborns, and pregnant women, after exposure to VZV and has shown some protection against chickenpox. However, the relative contribution of antibodies against individual surface glycoproteins toward protection from shingles in elderly/immunocompromised individuals has not been established. Here, we examined the breadth and functionality of VZV-specific antibodies after vaccination with the live attenuated VZV vaccine Zostavax in humans. This study will add to our understanding of the role of antibodies in protection against shingles.

Costimulatory Effects of an Immunodominant Parasite Antigen Paradoxically Prevent Induction of Optimal CD8 T Cell Protective Immunity.

Trypanosoma cruzi infection is controlled but not eliminated by host immunity. The T. cruzi trans-sialidase (TS) gene superfamily encodes immunodominant protective antigens, but expression of altered peptide ligands by different TS genes has been hypothesized to promote immunoevasion. We molecularly defined TS epitopes to determine their importance for protection versus parasite persistence. Peptide-pulsed dendritic cell vaccination experiments demonstrated that one pair of immunodominant CD4+ and CD8+ TS peptides alone can induce protective immunity (100% survival post-lethal parasite challenge). TS DNA vaccines have been shown by us (and others) to protect BALB/c mice against T. cruzi challenge. We generated a new TS vaccine in which the immunodominant TS CD8+ epitope MHC anchoring positions were mutated, rendering the mutant TS vaccine incapable of inducing immunity to the immunodominant CD8 epitope. Immunization of mice with wild type (WT) and mutant TS vaccines demonstrated that vaccines encoding enzymatically active protein and the immunodominant CD8+ T cell epitope enhance subdominant pathogen-specific CD8+ T cell responses. More specifically, CD8+ T cells from WT TS DNA vaccinated mice were responsive to 14 predicted CD8+ TS epitopes, while T cells from mutant TS DNA vaccinated mice were responsive to just one of these 14 predicted TS epitopes. Molecular and structural biology studies revealed that this novel costimulatory mechanism involves CD45 signaling triggered by enzymatically active TS. This enhancing effect on subdominant T cells negatively regulates protective immunity. Using peptide-pulsed DC vaccination experiments, we have shown that vaccines inducing both immunodominant and subdominant epitope responses were significantly less protective than vaccines inducing only immunodominant-specific responses. These results have important implications for T. cruzi vaccine development. Of broader significance, we demonstrate that increasing breadth of T cell epitope responses induced by vaccination is not always advantageous for host immunity.

Deficiency of antigen-specific B cells results in decreased Trypanosoma cruzi systemic but not mucosal immunity due to CD8 T cell exhaustion.

Vaccines against mucosally invasive, intracellular pathogens must induce a myriad of immune responses to provide optimal mucosal and systemic protection, including CD4(+) T cells, CD8(+) T cells, and Ab-producing B cells. In general, CD4(+) T cells are known to provide important helper functions for both CD8(+) T cell and B cell responses. However, the relative importance of CD4(+) T cells, CD8(+) T cells, and B cells for mucosal protection is less clearly defined. We have studied these questions in detail using the murine model of Trypanosoma cruzi infection. Despite our initial hypothesis that mucosal Abs would be important, we show that B cells are critical for systemic, but not mucosal, T. cruzi protective immunity. B cell-deficient mice developed normal levels of CD8(+) effector T cell responses early after mucosal T. cruzi infection and T. cruzi trans-sialidase vaccination. However, after highly virulent systemic challenge, T. cruzi immune mice lacking T. cruzi-specific B cells failed to control parasitemia or prevent death. Mechanistically, T. cruzi-specific CD8(+) T cells generated in the absence of B cells expressed increased PD-1 and Lag-3 and became functionally exhausted after high-level T. cruzi systemic challenge. T. cruzi immune serum prevented CD8(+) T cell functional exhaustion and reduced mortality in mice lacking B cells. Overall, these results demonstrate that T. cruzi-specific B cells are necessary during systemic, but not mucosal, parasite challenge.

Broadly reactive human CD8 T cells that recognize an epitope conserved between VZV, HSV and EBV.

Human herpesviruses are important causes of potentially severe chronic infections for which T cells are believed to be necessary for control. In order to examine the role of virus-specific CD8 T cells against Varicella Zoster Virus (VZV), we generated a comprehensive panel of potential epitopes predicted in silico and screened for T cell responses in healthy VZV seropositive donors. We identified a dominant HLA-A*0201-restricted epitope in the VZV ribonucleotide reductase subunit 2 and used a tetramer to analyze the phenotype and function of epitope-specific CD8 T cells. Interestingly, CD8 T cells responding to this VZV epitope also recognized homologous epitopes, not only in the other α-herpesviruses, HSV-1 and HSV-2, but also the γ-herpesvirus, EBV. Responses against these epitopes did not depend on previous infection with the originating virus, thus indicating the cross-reactive nature of this T cell population. Between individuals, the cells demonstrated marked phenotypic heterogeneity. This was associated with differences in functional capacity related to increased inhibitory receptor expression (including PD-1) along with decreased expression of co-stimulatory molecules that potentially reflected their stimulation history. Vaccination with the live attenuated Zostavax vaccine did not efficiently stimulate a proliferative response in this epitope-specific population. Thus, we identified a human CD8 T cell epitope that is conserved in four clinically important herpesviruses but that was poorly boosted by the current adult VZV vaccine. We discuss the concept of a "pan-herpesvirus" vaccine that this discovery raises and the hurdles that may need to be overcome in order to achieve this.

Antigen-specific TGF-ß-induced regulatory T cells secrete chemokines, regulate T cell trafficking, and suppress ongoing autoimmunity.

The ability to regulate ongoing inflammation using regulatory T cells (Tregs) is under intense investigation. Strategies to induce and expand Ag-specific Tregs are being developed, and whether various types of Tregs are suppressive in the inflammatory conditions associated with ongoing disease needs to be determined. In this study, we report that TGF-ß-induced Tregs (iTregs) and expanded Tregs specific for a major self-Ag in autoimmune gastritis suppress inflammation and associated pathology when administered late in the process of ongoing disease. Transferred iTregs localized to the stomach, maintained Foxp3 and suppressor functions, and engaged several distinct mechanisms to alleviate disease progression. In addition to suppressing the production of inflammatory cytokines in the stomach and preventing the destruction of parietal cells, we show that iTregs secrete numerous chemokines and regulate both iTreg and effector T cell trafficking into the stomach. These data support efforts to use iTregs in therapies to treat autoimmunity and inflammatory diseases and provide novel insight into the biological mechanisms of iTreg-mediated immune suppression.

Importance of the CCR5-CCL5 axis for mucosal Trypanosoma cruzi protection and B cell activation.

Trypanosoma cruzi is an intracellular parasite and the causative agent of Chagas disease. Previous work has shown that the chemokine receptor CCR5 plays a role in systemic T. cruzi protection. We evaluated the importance of CCR5 and CCL5 for mucosal protection against natural oral and conjunctival T. cruzi challenges. T. cruzi-immune CCR5(-/-) and wild-type C57BL/6 mice were generated by repeated infectious challenges with T. cruzi. CCR5(-/-) and wild-type mice developed equivalent levels of cellular, humoral, and protective mucosal responses. However, CCR5(-/-)-immune mice produced increased levels of CCL5 in protected gastric tissues, suggesting compensatory signaling through additional receptors. Neutralization of CCL5 in CCR5(-/-)-immune mice resulted in decreased mucosal inflammatory responses, reduced T. cruzi-specific Ab-secreting cells, and significantly less mucosal T. cruzi protection, confirming an important role for CCL5 in optimal immune control of T. cruzi replication at the point of initial mucosal invasion. To investigate further the mechanism responsible for mucosal protection mediated by CCL5-CCR5 signaling, we evaluated the effects of CCL5 on B cells. CCL5 enhanced proliferation and IgM secretion in highly purified B cells triggered by suboptimal doses of LPS. In addition, neutralization of endogenous CCL5 inhibited B cell proliferation and IgM secretion during stimulation of highly purified B cells, indicating that B cell production of CCL5 has important autocrine effects. These findings demonstrate direct effects of CCL5 on B cells, with significant implications for the development of mucosal adjuvants, and further suggest that CCL5 may be important as a general B cell coactivator.

Single cell multi-omic reference atlases of non-human primate immune tissues reveals CD102 as a biomarker for long-lived plasma cells.

In response to infection or immunization, antibodies are produced that provide protection against re-exposure with the same pathogen. These antibodies can persist at high titers for decades and are maintained by bone marrow-resident long-lived plasma cells (LLPC). However, the durability of antibody responses to immunization varies amongst vaccines. It is unknown what factors contribute to the differential longevity of serum antibody responses and whether heterogeneity in LLPC contributes to this phenomenon. While LLPC differentiation has been studied extensively in mice, little is known about this population in humans or non-human primates (NHP). Here, we use multi-omic single-cell profiling to identify and characterize the LLPC compartment in NHP. We identify LLPC biomarkers including the marker CD102 and show that CD102 in combination with CD31 identifies LLPC in NHP bone marrow. Additionally, we find that CD102 is expressed by LLPC in mouse and humans. These results further our understanding of the LLPC compartment in NHP, identify biomarkers of LLPC, and provide tissue-specific single cell references for future studies.

Profiling of hMPV F-specific antibodies isolated from human memory B cells.

Human metapneumovirus (hMPV) belongs to the Pneumoviridae family and is closely related to respiratory syncytial virus (RSV). The surface fusion (F) glycoprotein mediates viral fusion and is the primary target of neutralizing antibodies against hMPV. Here we report 113 hMPV-F specific monoclonal antibodies (mAbs) isolated from memory B cells of human donors. We characterize the antibodies' germline usage, epitopes, neutralization potencies, and binding specificities. We find that unlike RSV-F specific mAbs, antibody responses to hMPV F are less dominant against the apex of the antigen, and the majority of the potent neutralizing mAbs recognize epitopes on the side of hMPV F. Furthermore, neutralizing epitopes that differ from previously defined antigenic sites on RSV F are identified, and multiple binding modes of site V and II mAbs are discovered. Interestingly, mAbs that bind preferentially to the unprocessed prefusion F show poor neutralization potency. These results elucidate the immune recognition of hMPV infection and provide novel insights for future hMPV antibody and vaccine development.

Healthcare providers' perceived learning needs and barriers to providing care for chronic multisymptom illness and environmental exposure concerns.

OBJECTIVE: Patient provider encounters for chronic multisympom illness (CMI) and/or environmental exposures are difficult often resulting in Veterans and providers having high levels of dissatisfaction. Patients attribute these difficulties to providers lacking knowledge about these health concerns. It is not known whether providers perceive themselves as lacking expertise in CMI and environmental exposure concerns. METHODS: This needs assessment used a descriptive online survey design. A total of 3632 VA healthcare providers across disciplines were surveyed. RESULTS: Healthcare providers reported speaking with Veterans about CMI and environmental exposures despite feeling they have minimal to no knowledge of these topics. At the same time, only half of the providers had taken an available training on CMI or environmental exposure within the last year. CONCLUSION: Healthcare providers recognize a knowledge gap regarding CMI and environmental exposures, despite this, there is low uptake of provider education on these topics. PRACTICE IMPLICATIONS: A better understanding of barriers to uptake of training on CMI and environmental exposures is needed to increase engagement with these important trainings.

Veterans with Gulf War Illness perceptions of management strategies.

AIMS: Gulf War Illness (GWI) is a prevalent and disabling condition characterized by persistent physical symptoms. Clinical practice guidelines recommend self-management to reduce the disability from GWI. This study evaluated which GWI self-management strategies patients currently utilize and view as most effective and ineffective. MATERIALS AND METHODS: Data were collected from 267 Veterans during the baseline assessment of a randomized clinical trial for GWI. Respondents answered 3 open-ended questions regarding which self-management strategies they use, view as effective, and view as ineffective. Response themes were coded, and code frequencies were analyzed. KEY FINDINGS: Response frequencies varied across questions (in-use: n = 578; effective: n = 470; ineffective: n = 297). Healthcare use was the most commonly used management strategy (38.6% of 578), followed by lifestyle changes (28.5% of 578), positive coping (13% of 578), and avoidance (13.7% of 578). When asked about effective strategies, healthcare use (25.9% of 470), lifestyle change (35.7% of 470), and positive coping (17.4% of 470) were identified. Avoidance was frequently identified as ineffective (20.2% of 297 codes), as was invalidating experiences (14.1% of 297) and negative coping (10.4% of 297). SIGNIFICANCE: Patients with GWI use a variety of self-management strategies, many of which are consistent with clinical practice guidelines for treating GWI, including lifestyle change and non-pharmacological strategies. This suggests opportunities for providers to encourage effective self-management approaches that patients want to use.

Immunogenicity generated by mRNA vaccine encoding VZV gE antigen is comparable to adjuvanted subunit vaccine and better than live attenuated vaccine in nonhuman primates.

Shingles is a painful, blistering rash caused by reactivation of latent varicella-zoster virus (VZV) and most frequently occurs in elderly and immunocompromised individuals. Currently, two approved vaccines for the prevention of shingles are on the market, a live attenuated virus vaccine ZOSTAVAX® (Merck & Co., Inc., Kenilworth, NJ, USA) and an AS01B adjuvanted subunit protein vaccine Shingrix™ (Glaxo Smith Kline, Rockville, MD, USA). Human clinical immunogenicity and vaccine efficacy data is available for these two benchmark vaccines, offering a unique opportunity for comparative analyses with novel vaccine platforms and animal model translatability studies. The studies presented here utilized non-human primates (NHP) to evaluate humoral and cellular immune response by three vaccine modalities: the new platform of lipid nanoparticle (LNP) formulated mRNA encoding VZV gE antigen (VZV gE mRNA/LNP) as compared with well-established platforms of live attenuated VZV (VZV LAV) and adjuvanted VZV gE subunit protein (VZV gE protein/adjuvant). The magnitude of response to vaccination with a single 100-200 µg mRNA dose or two 50 µg mRNA doses of VZV gE mRNA/LNP were comparable to two 50 µg protein doses of VZV gE protein/adjuvant, suggesting the VZV gE mRNA/LNP platform has the potential to elicit a robust immune response, and both modalities generated markedly higher responses than VZV LAV. Additionally, the slopes of decay for VZV-specific antibody titers were roughly similar across all three vaccines, indicating the magnitude of peak immunogenicity was the driving force in determining immune response longevity. Finally, vaccine-induced immunogenicity with VZV LAV and VZV gE protein/adjuvant in NHP closely resembled human clinical trials immune response data for ZOSTAVAX® and Shingrix™, helping to validate NHP as an appropriate preclinical model for evaluating these vaccines.

Understanding the immunology of the Zostavax shingles vaccine.

Zostavax is a live-attenuated varicella zoster virus (VZV) vaccine recommended for use in adults >50 years of age to prevent shingles. The main risk factor for the development of shingles is age, which correlates with decreasing cell-mediated immunity. These data suggest a predominant role of T cell immunity in controlling VZV latency. However, other components of the immune system may also contribute. In this review, we will discuss how the immune system responds to Zostavax, focusing on recent studies examining innate immunity, transcriptomics, metabolomics, cellular, and humoral immunity.

Characterization of potent RSV neutralizing antibodies isolated from human memory B cells and identification of diverse RSV/hMPV cross-neutralizing epitopes.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children and older adults. Currently, no licensed vaccine is available, and therapeutic options are limited. The primary target of neutralizing antibodies to RSV is the surface fusion (F) glycoprotein. Understanding the recognition of antibodies with high neutralization potencies to RSV F antigen will provide critical insights in developing efficacious RSV antibodies and vaccines. In this study, we isolated and characterized a panel of monoclonal antibodies (mAbs) with high binding affinity to RSV prefusion F trimer and neutralization potency to RSV viruses. The mAbs were mapped to previously defined antigenic sites, and some that mapped to the same antigenic sites showed remarkable diversity in specificity, binding, and neutralization potencies. We found that the isolated site III mAbs shared highly conserved germline V-gene usage, but had different cross-reactivities to human metapneumovirus (hMPV), possibly due to the distinct modes/angles of interaction with RSV and hMPV F proteins. Furthermore, we identified a subset of potent RSV/hMPV cross-neutralizing mAbs that target antigenic site IV and the recently defined antigenic site V, while the majority of the mAbs targeting these two sites only neutralize RSV. Additionally, the isolated mAbs targeting site Ø were mono-specific for RSV and showed a wide range of neutralizing potencies on different RSV subtypes. Our data exemplify the diversity of anti-RSV mAbs and provide new insights into the immune recognition of respiratory viruses in the Pneumoviridae family.

Co-administration of a plasmid DNA encoding IL-15 improves long-term protection of a genetic vaccine against Trypanosoma cruzi.

BACKGROUND: Immunization of mice with the Trypanosoma cruzi trans-sialidase (TS) gene using plasmid DNA, adenoviral vector, and CpG-adjuvanted protein delivery has proven highly immunogenic and provides protection against acute lethal challenge. However, long-term protection induced by TS DNA vaccines has not been reported. The goal of the present work was to test whether the co-administration of a plasmid encoding IL-15 (pIL-15) could improve the duration of protection achieved through genetic vaccination with plasmid encoding TS (pTS) alone. METHODOLOGY: We immunized BALB/c mice with pTS in the presence or absence of pIL-15 and studied immune responses [with TS-specific IFN-γ ELISPOT, serum IgG ELISAs, intracellular cytokine staining (IFN-γ, TNF-α, and IL-2), tetramer staining, and CFSE dilution assays] and protection against lethal systemic challenge at 1 to 6 months post vaccination. Mice receiving pTS alone developed robust TS-specific IFN-γ responses and survived a lethal challenge given within the first 3 months following immunization. The addition of pIL-15 to pTS vaccination did not significantly alter T cell responses or protection during this early post-vaccination period. However, mice vaccinated with both pTS and pIL-15 challenged 6 months post-vaccination were significantly more protected against lethal T. cruzi challenges than mice vaccinated with pTS alone (P<0.05). Improved protection correlated with significantly higher numbers of TS-specific IFN-γ producing total and CD8(+) T cells detected>6 months post immunization. Also, these TS-specific T cells were better able to expand after in vitro re-stimulation. CONCLUSION: Addition of pIL-15 during genetic vaccination greatly improved long-term T cell survival, memory T cell expansion, and long-term protection against the important human parasite, T. cruzi.