Mosaic sarbecovirus nanoparticles elicit cross-reactive responses in pre-vaccinated animals.

Immunization with mosaic-8b (nanoparticles presenting 8 SARS-like betacoronavirus [sarbecovirus] receptor-binding domains [RBDs]) elicits more broadly cross-reactive antibodies than homotypic SARS-CoV-2 RBD-only nanoparticles and protects against sarbecoviruses. To investigate original antigenic sin (OAS) effects on mosaic-8b efficacy, we evaluated the effects of prior COVID-19 vaccinations in non-human primates and mice on anti-sarbecovirus responses elicited by mosaic-8b, admix-8b (8 homotypics), or homotypic SARS-CoV-2 immunizations, finding the greatest cross-reactivity for mosaic-8b. As demonstrated by molecular fate mapping, in which antibodies from specific cohorts of B cells are differentially detected, B cells primed by WA1 spike mRNA-LNP dominated antibody responses after RBD-nanoparticle boosting. While mosaic-8b- and homotypic-nanoparticles boosted cross-reactive antibodies, de novo antibodies were predominantly induced by mosaic-8b, and these were specific for variant RBDs with increased identity to RBDs on mosaic-8b. These results inform OAS mechanisms and support using mosaic-8b to protect COVID-19-vaccinated/infected humans against as-yet-unknown SARS-CoV-2 variants and animal sarbecoviruses with human spillover potential.

Transcriptional dysregulation of inflammatory/immune pathways after active vaccination against Huntington's disease.

Immunotherapy, both active and passive, is increasingly recognized as a powerful approach to a wide range of diseases, including Alzheimer's and Parkinson's. Huntington's disease (HD), an autosomal dominant disorder triggered by misfolding of huntingtin (HTT) protein with an expanded polyglutamine tract, could also benefit from this approach. Individuals can be identified genetically at the earliest stages of disease, and there may be particular benefits to a therapy that can target peripheral tissues in addition to brain. In this active vaccination study, we first examined safety and immunogenicity for a broad series of peptide, protein and DNA plasmid immunization protocols, using fragment (R6/1), and knock-in (zQ175) models. No safety issues were found. The strongest and most uniform immune response was to a combination of three non-overlapping HTT Exon1 coded peptides, conjugated to KLH, delivered with alum adjuvant. An N586-82Q plasmid, delivered via gene gun, also showed ELISA responses, mainly in the zQ175 strain, but with more variability, and less robust responses in HD compared with wild-type controls. Transcriptome profiling of spleens from the triple peptide-immunized cohort showed substantial HD-specific differences including differential activation of genes associated with innate immune responses, absence of negative feedback control of gene expression by regulators, a temporal dysregulation of innate immune responses and transcriptional repression of genes associated with memory T cell responses. These studies highlight critical issues for immunotherapy and HD disease management in general.

Mosaic sarbecovirus nanoparticles elicit cross-reactive responses in pre-vaccinated animals.

Immunization with mosaic-8b [60-mer nanoparticles presenting 8 SARS-like betacoronavirus (sarbecovirus) receptor-binding domains (RBDs)] elicits more broadly cross-reactive antibodies than homotypic SARS-CoV-2 RBD-only nanoparticles and protects against sarbecoviruses. To investigate original antigenic sin (OAS) effects on mosaic-8b efficacy, we evaluated effects of prior COVID-19 vaccinations in non-human primates and mice on anti-sarbecovirus responses elicited by mosaic-8b, admix-8b (8 homotypics), or homotypic SARS-CoV-2 immunizations, finding greatest cross-reactivity for mosaic-8b. As demonstrated by molecular fate-mapping in which antibodies from specific cohorts of B cells are differentially detected, B cells primed by WA1 spike mRNA-LNP dominated antibody responses after RBD-nanoparticle boosting. While mosaic-8b- and homotypic-nanoparticles boosted cross-reactive antibodies, de novo antibodies were predominantly induced by mosaic-8b, and these were specific for variant RBDs with increased identity to RBDs on mosaic-8b. These results inform OAS mechanisms and support using mosaic-8b to protect COVID-19 vaccinated/infected humans against as-yet-unknown SARS-CoV-2 variants and animal sarbecoviruses with human spillover potential.

Correction: Sustained AAV9-mediated expression of a non-self protein in the CNS of non-human primates after immunomodulation.

[This corrects the article DOI: 10.1371/journal.pone.0198154.].

Sustained AAV9-mediated expression of a non-self protein in the CNS of non-human primates after immunomodulation.

A critical issue in transgene delivery studies is immune reactivity to the transgene- encoded protein and its impact on sustained gene expression. Here, we test the hypothesis that immunomodulation by rapamycin can decrease immune reactivity after intrathecal AAV9 delivery of a transgene (GFP) in non-human primates, resulting in sustained GFP expression in the CNS. We show that rapamycin treatment clearly reduced the overall immunogenicity of the AAV9/GFP vector by lowering GFP- and AAV9-specific antibody responses, and decreasing T cell responses including cytokine and cytolytic effector responses. Spinal cord GFP protein expression was sustained for twelve weeks, with no toxicity. Immune correlates of robust transgene expression include negligible GFP-specific CD4 and CD8 T cell responses, absence of GFP-specific IFN-γ producing T cells, and absence of GFP-specific cytotoxic T cells, which support the hypothesis that decreased T cell reactivity results in sustained transgene expression. These data strongly support the use of modest doses of rapamycin to modulate immune responses for intrathecal gene therapies, and potentially a much wider range of viral vector-based therapeutics.

Coxsackievirus-induced pancreatitis.

In humans, infections with the group B coxsackieviruses (CVBs) range from asymptomatic infections to chronic, debilitating diseases. The CVBs are associated with chronic inflammatory diseases of the pancreas, heart, and central nervous system. A major focus in CVB pathogenesis is to understand the mechanisms by which these viruses cause acute diseases that resolve or acute diseases that progress to chronic diseases. The present review explores CVB infections in the development of acute and chronic pancreatitis. Mouse models of CVB-induced pancreatitis share many features with the human diseases and are providing insight into the multi-faceted processes of pancreatic tissue repair and irreversible tissue destruction. The development and progression of CVB-induced pancreatic inflammatory disease is an extremely complex process, involving both viral and host factors. The review examines the roles of the virus and host in contributing to the disease process. Recent studies of global gene expression during CVB-induced pancreatitis have increased our understanding of host factors that influence the outcome of infection and have highlighted interrelationships among complex biological programs. As we unravel the complexity of the disease process, the information gained will lead to the design of therapeutics that not only prevent the progression of chronic inflammatory disease, but that also restore functionality of affected tissues and organs.

Induction of mucosal HIV-specific B and T cell responses after oral immunization with live coxsackievirus B4 recombinants.

Given the limited success of clinical HIV vaccine trials, new vaccine strategies are needed for the HIV pipeline. The present study explored the novel concept that a live enteric virus, with limited disease potential, is a suitable vaccine vector to elicit HIV-specific immune responses in the gut mucosa of immunized mice. Two coxsackievirus B4 (CVB4) vaccine vectors were designed to induce HIV-specific B or T cell responses. A B cell immunogen, CVB4/gp41(2F5), was constructed by expressing an epitope from the membrane proximal external region (MPER) of gp41 as a structural peptide within a surface loop of a capsid protein of CVB4. The T cell immunogen, CVB4/p24(73(3)), was constructed previously by expressing a gag p24 sequence as a non-structural peptide at the amino-terminus of the CVB4 polyprotein. The CVB4/gp41(2F5) recombinant was antigenic in mice and elicited anti-gp41 antibodies in both the mucosal and systemic compartments. The route of immunization affected the antibody response since oral delivery of CVB4/gp41(2F5) induced anti-gp41 antibodies in the mucosal but not in the systemic compartment while parenteral delivery induced anti-gp41 antibodies in both compartments. In contrast, oral immunization with CVB4/p24(73(3)) elicited both mucosal and systemic gag p24-specific T cell responses. Since coxsackieviruses are ubiquitous in the human population, a key question is whether pre-existing vector immunity will inhibit the ability of a CVB4-based vaccine to induce HIV-specific immune responses. We show that pre-existing vector immunity did not preclude the development of mucosal anti-gp41 antibodies or gag p24-specific T cell responses after oral immunization with the CVB4/HIV recombinants. We suggest that the CVB4/HIV recombinants have the potential to be a viable vaccine product because of ease of delivery, safety, immunogenicity, ease of large-scale production, and storage conditions requiring cold-chain temperatures provided by refrigeration.

Dynamics of molecular responses to coxsackievirus B4 infection differentiate between resolution and progression of acute pancreatitis.

A coxsackievirus B4 induces acute pancreatitis with different outcomes. The study utilized a systems biology approach to identify molecular immune responses that differentiate between disease resolution and disease progression. The data establish a temporal pattern of host responses that differentiate the resolution of acute pancreatitis from the progression to chronic pancreatitis. A group of twenty-five genes exhibited characteristic expression profiles that were observed during the development of chronic pancreatitis but not during the resolution of disease. We postulate that the temporal dynamics of the twenty-five genes influence the development of pathogenic immune responses associated with chronic pancreatitis. Furthermore, a subset of eleven genes exhibited increased expression as viral titers waned. Of the eleven gene products, five are secreted molecules, TNF-α, IFN-γ, CXCL10, IL-10, and IL-22b, and represent novel potential therapeutic targets since they can be readily modulated with antibodies against the specific cytokine/chemokine or with antibodies against the corresponding receptors.

Oral immunization with a live coxsackievirus/HIV recombinant induces gag p24-specific T cell responses.

BACKGROUND: The development of an HIV/AIDS vaccine has proven to be elusive. Because human vaccine trials have not yet demonstrated efficacy, new vaccine strategies are needed for the HIV vaccine pipeline. We have been developing a new HIV vaccine platform using a live enterovirus, coxsackievirus B4 (CVB4) vector. Enteroviruses are ideal candidates for development as a vaccine vector for oral delivery, because these viruses normally enter the body via the oral route and survive the acidic environment of the stomach. METHODOLOGY/PRINCIPAL FINDINGS: We constructed a live coxsackievirus B4 recombinant, CVB4/p24(73(3)), that expresses seventy-three amino acids of the gag p24 sequence (HXB2) and assessed T cell responses after immunization of mice. The CVB4 recombinant was physically stable, replication-competent, and genetically stable. Oral or intraperitoneal immunization with the recombinant resulted in strong systemic gag p24-specific T cell responses as determined by the IFN-gamma ELISPOT assay and by multiparameter flow cytometry. Oral immunization with CVB4/p24(73(3)) resulted in a short-lived, localized infection of the gut without systemic spread. Because coxsackieviruses are ubiquitous in the human population, we also evaluated whether the recombinant was able to induce gag p24-specific T cell responses in mice pre-immunized with the CVB4 vector. We showed that oral immunization with CVB4/p24(73(3)) induced gag p24-specific immune responses in vector-immune mice. CONCLUSIONS/SIGNIFICANCE: The CVB4/p24(73(3)) recombinant retained the physical and biological characteristics of the parental CVB4 vector. Oral immunization with the CVB4 recombinant was safe and resulted in the induction of systemic HIV-specific T cell responses. Furthermore, pre-existing vector immunity did not preclude the development of gag p24-specific T cell responses. As the search continues for new vaccine strategies, the present study suggests that live CVB4/HIV recombinants are potential new vaccine candidates for HIV.

IL-10 is pathogenic during the development of coxsackievirus B4-induced chronic pancreatitis.

Using a mouse model of coxsackievirus B4 (CVB4-V)-induced chronic pancreatitis, we investigated whether cytokines are involved in the progression of acute disease to chronic inflammatory disease. We show that IL-10 contributed to the development of chronic pancreatitis since acute disease resolved when IL-10 was absent or when IL-10 signaling was disrupted. We explored the underlying mechanisms by which IL-10 affected disease progression, using a novel approach to assess immunological events occurring in situ. Multiple markers that define functional innate immune responses and functional T cell responses were monitored over the course of CVB4-V infection of wild-type and IL-10 knockout mice, using a multiplex transcriptional profiling approach. We show that high levels of IL-10 early during infection were associated with delayed innate and T cell responses. Furthermore, high IL-10 production correlated with altered kinetics of T regulatory responses indicating a disruption in the balance between effector and regulatory T cell responses.

Progression or resolution of coxsackievirus B4-induced pancreatitis: a genomic analysis.

Group B coxsackieviruses are associated with chronic inflammatory diseases of the pancreas, heart, and central nervous system. Chronic pancreatitis, which can develop from acute pancreatitis, is considered a premalignant disorder because it is a major risk factor for pancreatic cancer. To explore the genetic events underlying the progression of acute to chronic disease, a comparative analysis of global gene expression during coxsackievirus B4-induced acute and chronic pancreatitis was undertaken. A key feature of acute pancreatitis that resolved was tissue regeneration, which was accompanied by increased expression of genes involved in cell growth, inhibition of apoptosis, and embryogenesis and by increased division of acinar cells. Acute pancreatitis that progressed to chronic pancreatitis was characterized by lack of tissue repair, and the expression map highlighted genes involved in apoptosis, acinoductular metaplasia, remodeling of the extracellular matrix, and fibrosis. Furthermore, immune responses appeared skewed toward development of alternatively activated (M2) macrophages and T helper 2 (Th2) cells during disease that resolved and toward classically activated (M1) macrophages and Th1 cells during disease that progressed. Our hypothesis is that growth and differentiation signals coupled with the M2/Th2 milieu favor acinar cell proliferation, while diminished growth signals and the M1/Th1 milieu favor apoptosis of acinar cells and remodeling/proliferation of the extracellular matrix, resulting in fibrosis.

Exogenous interleukin-12 protects against lethal infection with coxsackievirus B4.

Infections with the group B coxsackieviruses either can be asymptomatic or can lead to debilitating chronic diseases. To elucidate the mechanism by which these viruses cause chronic disease, we developed a mouse model of chronic pancreatitis by using a virulent variant of coxsackievirus B4, CVB4-V. Infection with CVB4-V results in an early, severe pancreatitis, which can lead to mortality or progress to chronic pancreatitis. Chronic pancreatitis, in this model, is due to immunopathological mechanisms. We investigated whether interleukin-12 (IL-12) could modulate the outcome of CVB4-V infection. Eighty-five percent of the infected mice treated with 500 ng of IL-12 survived, whereas all untreated mice succumbed. To understand the mechanism underlying the beneficial effect of IL-12, we investigated the role of gamma interferon (IFN-gamma). Three lines of evidence suggest that the protective effect of IL-12 is due to IFN-gamma. First, administration of IL-12 increased the production of endogenous IFN-gamma in CVB4-V-infected mice. Both NK and NKT cells were identified as the source of IFN-gamma. Second, IFN-gamma knockout mice treated with IL-12 succumbed to infection with CVB4-V. Third, wild-type mice treated with IFN-gamma survived infection with CVB4-V. Due to the antiviral effects of IFN-gamma, we examined whether IL-12 treatment affected viral replication. Administration of IL-12 did not decrease viral replication in the pancreas, but it did prevent extensive tissue damage and the subsequent development of chronic pancreatitis. The data suggest that IL-12 treatment during CVB4-V infection is able to suppress the immunopathological mechanisms that lead to chronic disease.