Time-resolved systems immunology reveals a late juncture linked to fatal COVID-19.

COVID-19 exhibits extensive patient-to-patient heterogeneity. To link immune response variation to disease severity and outcome over time, we longitudinally assessed circulating proteins as well as 188 surface protein markers, transcriptome, and T cell receptor sequence simultaneously in single peripheral immune cells from COVID-19 patients. Conditional-independence network analysis revealed primary correlates of disease severity, including gene expression signatures of apoptosis in plasmacytoid dendritic cells and attenuated inflammation but increased fatty acid metabolism in CD56dimCD16hi NK cells linked positively to circulating interleukin (IL)-15. CD8+ T cell activation was apparent without signs of exhaustion. Although cellular inflammation was depressed in severe patients early after hospitalization, it became elevated by days 17-23 post symptom onset, suggestive of a late wave of inflammatory responses. Furthermore, circulating protein trajectories at this time were divergent between and predictive of recovery versus fatal outcomes. Our findings stress the importance of timing in the analysis, clinical monitoring, and therapeutic intervention of COVID-19.

Epstein-Barr virus gp42 antibodies reveal sites of vulnerability for receptor binding and fusion to B cells.

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with B cell lymphomas. EBV glycoprotein 42 (gp42) binds HLA class II and activates membrane fusion with B cells. We isolated gp42-specific monoclonal antibodies (mAbs), A10 and 4C12, which use distinct mechanisms to neutralize virus infection. mAb A10 was more potent than the only known neutralizing gp42 mAb, F-2-1, in neutralizing EBV infection and blocking binding to HLA class II. mAb 4C12 was similar to mAb A10 in inhibiting glycoprotein-mediated B cell fusion but did not block receptor binding, and it was less effective in neutralizing infection. Crystallographic structures of gH/gL/gp42/A10 and gp42/4C12 complexes revealed two distinct sites of vulnerability on gp42 for receptor binding and B cell fusion. Passive transfer of mAb A10 into humanized mice conferred nearly 100% protection from viremia and EBV lymphomas after EBV challenge. These findings identify vulnerable sites on EBV that may facilitate therapeutics and vaccines.

Epstein-Barr virus gH/gL has multiple sites of vulnerability for virus neutralization and fusion inhibition.

Epstein-Barr virus (EBV) is nearly ubiquitous in adults. EBV causes infectious mononucleosis and is associated with B cell lymphomas, epithelial cell malignancies, and multiple sclerosis. The EBV gH/gL glycoprotein complex facilitates fusion of virus membrane with host cells and is a target of neutralizing antibodies. Here, we examined the sites of vulnerability for virus neutralization and fusion inhibition within EBV gH/gL. We developed a panel of human monoclonal antibodies (mAbs) that targeted five distinct antigenic sites on EBV gH/gL and prevented infection of epithelial and B cells. Structural analyses using X-ray crystallography and electron microscopy revealed multiple sites of vulnerability and defined the antigenic landscape of EBV gH/gL. One mAb provided near-complete protection against viremia and lymphoma in a humanized mouse EBV challenge model. Our findings provide structural and antigenic knowledge of the viral fusion machinery, yield a potential therapeutic antibody to prevent EBV disease, and emphasize gH/gL as a target for herpesvirus vaccines and therapeutics.

Rational Design of an Epstein-Barr Virus Vaccine Targeting the Receptor-Binding Site.

Epstein-Barr virus (EBV) represents a major global health problem. Though it is associated with infectious mononucleosis and ∼200,000 cancers annually worldwide, a vaccine is not available. The major target of immunity is EBV glycoprotein 350/220 (gp350) that mediates attachment to B cells through complement receptor 2 (CR2/CD21). Here, we created self-assembling nanoparticles that displayed different domains of gp350 in a symmetric array. By focusing presentation of the CR2-binding domain on nanoparticles, potent neutralizing antibodies were elicited in mice and non-human primates. The structurally designed nanoparticle vaccine increased neutralization 10- to 100-fold compared to soluble gp350 by targeting a functionally conserved site of vulnerability, improving vaccine-induced protection in a mouse model. This rational approach to EBV vaccine design elicited potent neutralizing antibody responses by arrayed presentation of a conserved viral entry domain, a strategy that can be applied to other viruses.

Immunization with Components of the Viral Fusion Apparatus Elicits Antibodies That Neutralize Epstein-Barr Virus in B Cells and Epithelial Cells.

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with epithelial-cell cancers and B cell lymphomas. An effective EBV vaccine is not available. We found that antibodies to the EBV glycoprotein gH/gL complex were the principal components in human plasma that neutralized infection of epithelial cells and that antibodies to gH/gL and gp42 contributed to B cell neutralization. Immunization of mice and nonhuman primates with nanoparticle vaccines that displayed components of the viral-fusion machinery EBV gH/gL or gH/gL/gp42 elicited antibodies that potently neutralized both epithelial-cell and B cell infection. Immune serum from nonhuman primates inhibited EBV-glycoprotein-mediated fusion of epithelial cells and B cells and targeted an epitope critical for virus-cell fusion. Therefore, unlike the leading EBV gp350 vaccine candidate, which only protects B cells from infection, these EBV nanoparticle vaccines elicit antibodies that inhibit the virus-fusion apparatus and provide cell-type-independent protection from virus infection.

SARS-CoV-2 infection and persistence in the human body and brain at autopsy.

Coronavirus disease 2019 (COVID-19) is known to cause multi-organ dysfunction1-3 during acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some patients experiencing prolonged symptoms, termed post-acute sequelae of SARS-CoV-2 (refs. 4,5). However, the burden of infection outside the respiratory tract and time to viral clearance are not well characterized, particularly in the brain3,6-14. Here we carried out complete autopsies on 44 patients who died with COVID-19, with extensive sampling of the central nervous system in 11 of these patients, to map and quantify the distribution, replication and cell-type specificity of SARS-CoV-2 across the human body, including the brain, from acute infection to more than seven months following symptom onset. We show that SARS-CoV-2 is widely distributed, predominantly among patients who died with severe COVID-19, and that virus replication is present in multiple respiratory and non-respiratory tissues, including the brain, early in infection. Further, we detected persistent SARS-CoV-2 RNA in multiple anatomic sites, including throughout the brain, as late as 230 days following symptom onset in one case. Despite extensive distribution of SARS-CoV-2 RNA throughout the body, we observed little evidence of inflammation or direct viral cytopathology outside the respiratory tract. Our data indicate that in some patients SARS-CoV-2 can cause systemic infection and persist in the body for months.

Structural insights into hepatitis C virus receptor binding and entry.

Hepatitis C virus (HCV) infection is a causal agent of chronic liver disease, cirrhosis and hepatocellular carcinoma in humans, and afflicts more than 70 million people worldwide. The HCV envelope glycoproteins E1 and E2 are responsible for the binding of the virus to the host cell, but the exact entry process remains undetermined1. The majority of broadly neutralizing antibodies block interaction between HCV E2 and the large extracellular loop (LEL) of the cellular receptor CD81 (CD81-LEL)2. Here we show that low pH enhances the binding of CD81-LEL to E2, and we determine the crystal structure of E2 in complex with an antigen-binding fragment (2A12) and CD81-LEL (E2-2A12-CD81-LEL); E2 in complex with 2A12 (E2-2A12); and CD81-LEL alone. After binding CD81, residues 418-422 in E2 are displaced, which allows for the extension of an internal loop consisting of residues 520-539. Docking of the E2-CD81-LEL complex onto a membrane-embedded, full-length CD81 places the residues Tyr529 and Trp531 of E2 proximal to the membrane. Liposome flotation assays show that low pH and CD81-LEL increase the interaction of E2 with membranes, whereas structure-based mutants of Tyr529, Trp531 and Ile422 in the amino terminus of E2 abolish membrane binding. These data support a model in which acidification and receptor binding result in a conformational change in E2 in preparation for membrane fusion.

A nonhuman primate model for genital herpes simplex virus 2 infection that results in vaginal vesicular lesions, virus shedding, and seroconversion.

The most commonly used animal models for evaluating the efficacy of HSV-2 candidate vaccines are mice and guinea pigs. While numerous HSV-2 vaccine candidates have been tested in these animals and were effective in reducing disease and mortality, these results did not predict the effectiveness of the vaccines in human trials. Infection of rhesus macaques rarely results in lesions or HSV-2 specific antibody responses. In seeking an animal model that better recapitulates human disease and that might be more predictive of the efficacy of prophylactic vaccines than mice and guinea pigs, we evaluated Cebus apella (C. apella), a New World primate, in an HSV-2 genital infection model. Infectious HSV-2 was cultured from vaginal swabs from all 4 animals for 9-14 days after intravaginal inoculation of HSV-2 seronegative monkeys. Two of 4 monkeys had vesicular lesions in the vagina or vulva. No neurological symptoms were noted. Recurrent lesions and HSV-2 DNA shedding after acute disease resolved was infrequent. UV irradiation of the genital area did not induce recurrent genital lesions or virus shedding. All 4 monkeys developed HSV-2 neutralizing antibodies as well as virus-specific CD4 and CD8 T cell responses. Reinfection of animals 15 to 19 months after primary infection did not result in lesions; animals had reduced virus shedding and a shorter duration of shedding compared with that during primary infection, suggesting that primary infection induced protective immunity. Primary fibroblasts from C. apella monkeys supported the growth of HSV-2 in vitro; in contrast, HSV-2 did not replicate above the titer of the input inoculum in fibroblasts from rhesus macaques. These observations suggest that the C. apella monkey has potential to serve as a model for evaluating the efficacy of prophylactic vaccines, antivirals, or monoclonal antibodies to HSV-2.

Dominant-activating germline mutations in the gene encoding the PI(3)K catalytic subunit p110δ result in T cell senescence and human immunodeficiency.

The p110δ subunit of phosphatidylinositol-3-OH kinase (PI(3)K) is selectively expressed in leukocytes and is critical for lymphocyte biology. Here we report fourteen patients from seven families who were heterozygous for three different germline, gain-of-function mutations in PIK3CD (which encodes p110δ). These patients presented with sinopulmonary infections, lymphadenopathy, nodular lymphoid hyperplasia and viremia due to cytomegalovirus (CMV) and/or Epstein-Barr virus (EBV). Strikingly, they had a substantial deficiency in naive T cells but an over-representation of senescent effector T cells. In vitro, T cells from patients exhibited increased phosphorylation of the kinase Akt and hyperactivation of the metabolic checkpoint kinase mTOR, enhanced glucose uptake and terminal effector differentiation. Notably, treatment with rapamycin to inhibit mTOR activity in vivo partially restored the abundance of naive T cells, largely 'rescued' the in vitro T cell defects and improved the clinical course.

Pathogenesis and outcome of VA1 astrovirus infection in the human brain are defined by disruption of neural functions and imbalanced host immune responses.

Astroviruses (AstVs) can cause of severe infection of the central nervous system (CNS) in immunocompromised individuals. Here, we identified a human AstV of the VA1 genotype, HAstV-NIH, as the cause of fatal encephalitis in an immunocompromised adult. We investigated the cells targeted by AstV, neurophysiological changes, and host responses by analyzing gene expression, protein expression, and cellular morphology in brain tissue from three cases of AstV neurologic disease (AstV-ND). We demonstrate that neurons are the principal cells targeted by AstV in the brain and that the cerebellum and brainstem have the highest burden of infection. Detection of VA1 AstV in interconnected brain structures such as thalamus, deep cerebellar nuclei, Purkinje cells, and pontine nuclei indicates that AstV may spread between connected neurons transsynaptically. We found transcriptional dysregulation of neural functions and disruption of both excitatory and inhibitory synaptic innervation of infected neurons. Importantly, transcriptional dysregulation of neural functions occurred in fatal cases, but not in a patient that survived AstV-ND. We show that the innate, but not adaptive immune response was transcriptionally driving host defense in the brain of immunocompromised patients with AstV-ND. Both transcriptome and molecular pathology studies showed that most of the cellular changes were associated with CNS-intrinsic cells involved in phagocytosis and injury repair (microglia, perivascular/parenchymal border macrophages, and astrocytes), but not CNS-extrinsic cells (T and B cells), suggesting an imbalance of innate and adaptive immune responses to AstV infection in the brain as a result of the underlying immunodeficiencies. These results show that VA1 AstV infection of the brain in immunocompromised humans is associated with imbalanced host defense responses, disruption of neuronal somatodendritic compartments and synapses and increased phagocytic cellular activity. Improved understanding of the response to viral infections of the human CNS may provide clues for how to manipulate these processes to improve outcomes.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee.

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Comparison of Levels of Nasal, Salivary, and Plasma Antibody to Severe Acute Respiratory Syndrome Coronavirus 2 During Natural Infection and After Vaccination.

BACKGROUND: Most studies of immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) measure antibody or cellular responses in blood; however, the virus infects mucosal surfaces in the nose and conjunctivae and infectious virus is rarely if ever present in the blood. METHODS: We used luciferase immunoprecipitation assays to measure SARS-CoV-2 antibody levels in the plasma, nose, and saliva of infected persons and vaccine recipients. These assays measure antibody that can precipitate the SAR-CoV-2 spike and nucleocapsid proteins. RESULTS: Levels of plasma anti-spike antibody declined less rapidly than levels of anti-nucleocapsid antibody in infected persons. SARS-CoV-2 anti-spike antibody levels in the nose declined more rapidly than antibody levels in the blood after vaccination of infected persons. Vaccination of previously infected persons boosted anti-spike antibody in plasma more than in the nose or saliva. Nasal and saliva anti-spike antibody levels were significantly correlated with plasma antibody in infected persons who had not been vaccinated and after vaccination of uninfected persons. CONCLUSIONS: Persistently elevated SARS-CoV-2 antibody in plasma may not indicate persistence of antibody at mucosal sites such as the nose. The strong correlation of SARS-CoV-2 antibody in the nose and saliva with that in the blood suggests that mucosal antibodies are derived primarily from transudation from the blood rather than local production. While SARS-CoV-2 vaccine given peripherally boosted mucosal immune responses in infected persons, the increase in antibody titers was higher in plasma than at mucosal sites. Taken together, these observations indicate the need for development of mucosal vaccines to induce potent immune responses at sites where SARS-CoV-2 infection occurs. CLINICAL TRIALS REGISTRATION: NCT01306084.

Successful lung transplantation using an allograft from a COVID-19-recovered donor: a potential role for subgenomic RNA to guide organ utilization.

Although the risk of SARS-CoV-2 transmission through lung transplantation from acutely infected donors is high, the risks of virus transmission and long-term lung allograft outcomes are not as well described when using pulmonary organs from COVID-19-recovered donors. We describe successful lung transplantation for a COVID-19-related lung injury using lungs from a COVID-19-recovered donor who was retrospectively found to have detectable genomic SARS-CoV-2 RNA in the lung tissue by multiple highly sensitive assays. However, SARS-CoV-2 subgenomic RNA (sgRNA), a marker of viral replication, was not detectable in the donor respiratory tissues. One year after lung transplantation, the recipient has a good functional status, walking 1 mile several times per week without the need for supplemental oxygen and without any evidence of donor-derived SARS-CoV-2 transmission. Our findings highlight the limitations of current clinical laboratory diagnostic assays in detecting the persistence of SARS-CoV-2 RNA in the lung tissue. The persistence of SARS-CoV-2 RNA in the donor tissue did not appear to represent active viral replication via sgRNA testing and, most importantly, did not negatively impact the allograft outcome in the first year after lung transplantation. sgRNA is easily performed and may be a useful assay for assessing viral infectivity in organs from donors with a recent infection.

The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS).

OBJECTIVE: Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS. METHODS: A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS. RESULTS: The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance. CONCLUSION: These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

Characterization of B-cell receptor clonality and immunoglobulin gene usage at multiple time points during active SARS-CoV-2 infection.

Although monoclonal antibodies to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are known, B-cell receptor repertoire and its change in patients during coronavirus disease-2019 (COVID-19) progression is underreported. We aimed to study this molecularly. We used immunoglobulin heavy chain (IGH) variable region (IGHV) spectratyping and next-generation sequencing of peripheral blood B-cell genomic DNA collected at multiple time points during disease evolution to study B-cell response to SARS-CoV-2 infection in 14 individuals with acute COVID-19. We found a broad distribution of responding B-cell clones. The IGH gene usage was not significantly skewed but frequencies of individual IGH genes changed repeatedly. We found predominant usage of unmutated and low mutation-loaded IGHV rearrangements characterizing naïve and extrafollicular B cells among the majority of expanded peripheral B-cell clonal lineages at most tested time points in most patients. IGH rearrangement usage showed no apparent relation to anti-SARS-CoV-2 antibody titers. Some patients demonstrated mono/oligoclonal populations carrying highly mutated IGHV rearrangements indicating antigen experience at some of the time points tested, including even before anti-SARS-CoV-2 antibodies were detected. We present evidence demonstrating that the B-cell response to SARS-CoV-2 is individual and includes different lineages of B cells at various time points during COVID-19 progression.

Effect of Bruton tyrosine kinase inhibitor on efficacy of adjuvanted recombinant hepatitis B and zoster vaccines.

Vaccinations are effective in preventing infections; however, it is unknown if patients with chronic lymphocytic leukemia (CLL) who are treatment naïve (TN) or receiving Bruton tyrosine kinase inhibitors (BTKi's) respond to novel adjuvanted vaccines. Understanding the effect of BTKi's on humoral immunity is timely because BTKi's are widely used and vaccination against coronavirus disease 2019 is urgently needed. In 2 open-label, single-arm clinical trials, we measured the effect of BTKi's on de novo immune response against recombinant hepatitis B vaccine (HepB-CpG) and recall response against recombinant zoster vaccine (RZV) in CLL patients who were TN or on BTKi. The primary end point was serologic response to HepB-CpG (anti-hepatitis B surface antibodies ≥10 mIU/mL) and RZV (≥fourfold increase in anti-glycoprotein E). The response rate to HepB-CpG was lower in patients on BTKi (3.8%; 95% confidence interval [CI], 0.7-18.9) than patients who were TN (28.1%; 95% CI, 15.6-45.4; P = .017). In contrast, the response rate to RZV did not differ significantly between the BTKi (41.5%; 95% CI, 27.8-56.6) and TN cohorts (59.1%; 95% CI, 38.7-76.7; P = .2). BTKi's were associated with a decreased de novo immune response following HepB-CpG, whereas recall immune response following RZV was not significantly affected by BTKi therapy. These trials were registered at www.clinicaltrials.gov as #NCT03685708 (Hep-CpG) and #NCT03702231 (RZV).

A Double-Blind, Placebo-Controlled, Crossover Study of Magnesium Supplementation in Patients with XMEN Disease.

X-linked MAGT1 deficiency with increased susceptibility to Epstein-Barr virus (EBV) infection and N-linked glycosylation defect (XMEN) disease is an inborn error of immunity caused by loss-of-function mutations in the magnesium transporter 1 (MAGT1) gene. The original studies of XMEN patients focused on impaired magnesium regulation, leading to decreased EBV-cytotoxicity and the loss of surface expression of the activating receptor "natural killer group 2D" (NKG2D) on CD8+ T cells and NK cells. In vitro studies showed that supraphysiological supplementation of magnesium rescued these defects. Observational studies in 2 patients suggested oral magnesium supplementation could decrease EBV viremia. Hence, we performed a randomized, double-blind, placebo-controlled, crossover study in 2 parts. In part 1, patients received either oral magnesium L-threonate (MLT) or placebo for 12 weeks followed by 12 weeks of the other treatment. Part 2 began with 3 days of high-dose intravenous (IV) magnesium sulfate (MgSO4) followed by open-label MLT for 24 weeks. One EBV-infected and 3 EBV-naïve patients completed part 1. One EBV-naïve patient was removed from part 2 of the study due to asymptomatic elevation of liver enzymes during IV MgSO4. No change in EBV or NKG2D status was observed. In vitro magnesium supplementation experiments in cells from 14 XMEN patients failed to significantly rescue NKG2D expression and the clinical trial was stopped. Although small, this study indicates magnesium supplementation is unlikely to be an effective therapeutic option in XMEN disease.

Nectin-1 Is an Entry Mediator for Varicella-Zoster Virus Infection of Human Neurons.

Varicella-zoster virus (VZV) maintains lifelong latency in neurons following initial infection and can subsequently be reactivated to result in herpes zoster or severe neurological manifestations such as encephalitis. Mechanisms of VZV neuropathogenesis have been challenging to study due to the strict human tropism of the virus. Although neuronal entry mediators of other herpesviruses, including herpes simplex virus, have been identified, little is known regarding how VZV enters neurons. Here, we utilize a human stem cell-based neuronal model to characterize cellular factors that mediate entry. Through transcriptional profiling of infected cells, we identify the cell adhesion molecule nectin-1 as a candidate mediator of VZV entry. Nectin-1 is highly expressed in the cell bodies and axons of neurons. Either knockdown of endogenous nectin-1 or incubation with soluble forms of nectin-1 produced in mammalian cells results in a marked decrease in infectivity of neurons. Notably, while addition of soluble nectin-1 during viral infection inhibits infectivity, addition after infection has no effect on infectivity. Ectopic expression of human nectin-1 in a cell line resistant to productive VZV infection confers susceptibility to infection. In summary, we have identified nectin-1 as a neuronal entry mediator of VZV. IMPORTANCE Varicella-zoster virus (VZV) causes chickenpox, gains access to neurons during primary infection where it resides lifelong, and can later be reactivated. Reactivation is associated with shingles and postherpetic neuralgia, as well as with severe neurologic complications, including vasculitis and encephalitis. Although the varicella vaccine substantially decreases morbidity and mortality associated with primary infection, the vaccine cannot prevent the development of neuronal latency, and vaccinated populations are still at risk for reactivation. Furthermore, immunocompromised individuals are at higher risk for VZV reactivation and associated complications. Little is known regarding how VZV enters neurons. Here, we identify nectin-1 as an entry mediator of VZV in human neurons. Identification of nectin-1 as a neuronal VZV entry mediator could lead to improved treatments and preventative measures to reduce VZV related morbidity and mortality.

SARS-CoV-2-specific T cells are rapidly expanded for therapeutic use and target conserved regions of the membrane protein.

T-cell responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been described in recovered patients, and may be important for immunity following infection and vaccination as well as for the development of an adoptive immunotherapy for the treatment of immunocompromised individuals. In this report, we demonstrate that SARS-CoV-2-specific T cells can be expanded from convalescent donors and recognize immunodominant viral epitopes in conserved regions of membrane, spike, and nucleocapsid. Following in vitro expansion using a good manufacturing practice-compliant methodology (designed to allow the rapid translation of this novel SARS-CoV-2 T-cell therapy to the clinic), membrane, spike, and nucleocapsid peptides elicited interferon-γ production, in 27 (59%), 12 (26%), and 10 (22%) convalescent donors (respectively), as well as in 2 of 15 unexposed controls. We identified multiple polyfunctional CD4-restricted T-cell epitopes within a highly conserved region of membrane protein, which induced polyfunctional T-cell responses, which may be critical for the development of effective vaccine and T-cell therapies. Hence, our study shows that SARS-CoV-2 directed T-cell immunotherapy targeting structural proteins, most importantly membrane protein, should be feasible for the prevention or early treatment of SARS-CoV-2 infection in immunocompromised patients with blood disorders or after bone marrow transplantation to achieve antiviral control while mitigating uncontrolled inflammation.

Robust immune responses to SARS-CoV-2 in a pediatric patient with B-Cell ALL receiving tisagenlecleucel.

Recipients of anti-CD19 targeted therapies such as chimeric antigen receptor (CAR)-T cell are considered at high risk for complicated Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection due to prolonged B cell aplasia and immunosuppression. These patients represent a unique cohort and so far, immune responses to SARS-CoV-2 have not been well characterized in this setting. We report a pediatric patient with B-cell acute lymphoblastic leukemia (B-ALL) who had asymptomatic SARS-CoV-2 infection while receiving blinatumomab, followed by lymphodepletion (LD) and tisagenlecleucel, a CD19 targeting CAR-T therapy. The patient had a complete response to tisagenlecleucel, did not develop cytokine release syndrome, or worsening of SARS-CoV-2 during therapy. The patient had evidence of ongoing persistence of IgG antibody responses to spike and nucleocapsid after LD followed by tisagenlecleucel despite the B-cell aplasia. Further we were able to detect SARS-CoV-2 specific T-cells recognizing multiple viral structural proteins for several months following CAR-T. The T-cell response was polyfunctional and predominantly CD4 restricted. This data has important implications for the understanding of SARS-CoV-2 immunity in patients with impaired immune systems and the potential application of SARS-CoV-2-specific T-cell therapeutics to treat patients with blood cancers who receive B cell depleting therapy.