bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interferon gamma supresses T follicular helper cell and antibody responses upon viral infection
Authors: Kuka Mirela , Sala Eleonora , Mangione Marta , Laura Chiara , Nelli Maria , Consolo Eleonora , Beccaria Cristian Gabriel , Amit Ido , Iannacone Matteo 
Published: August 2023

Abstract
Although humoral and cellular immunity upon viral infections usually co-exist, sometimes one of the two responses emerges as dominant and is responsible for most of the antiviral activity. For example, vesicular stomatitis virus (VSV) infection induces early and potent neutralizing antibody (nAb) responses, whereas lymphocytic choriomeningitis virus (LCMV) infection induces strong cellular responses, but weak nAb responses. Recent work from our laboratory has shown that unbalance is observed also at the level of CD4 T cells responses, with subcutaneous VSV infection inducing strong TFH polarization that supports nAb responses, and subcutaneous LCMV in contrast promoting an extreme TH1 differentiation with no TFH. Single-cell RNA sequencing revealed that LCMV-specific TH1 cells comprise at least to distinct subsets, one of which expresses TCF1, which is usually expressed by TFH. We found that blocking of IFN gamma results in the transition of this atypical T-bet+TCF1+ cells into TFH cells, and in an increased number of germinal center B cells and antibodies. Our results identify IFN gamma as a molecular switch that suppresses TFH and antibody responses while supporting TH1 differentiation upon viral infection. This might be an additional mechanism whereby viruses like LCMV interfere with the generation of efficient antibody responses.
Research was supported by the Italian Ministry of Education, University and Research grants SIR-RBSI14BAO5, PRIN-2017ZXT5WR and PRIN-20209Y5YFZ (to M.K.) and by the European Research Council (ERC) Consolidator Grant 725038 (to M.I.)
The complement protein C1q modulates the activities of anti-influenza HA-stem and anti-SARS-Cov2-nonRBD antibodies and alters viral evolution
Authors: Kosik Ivan , Santos Jefferson J J , Angel Mathew , Hu Zhe , Holly Jaroslav , Gibbs James S , Gill Tanner U , Andrews Sarah , Gillespie Rebecca , Kanekiyo Masaru , Mcdermott Adrian , Yewdell Jonathan W 
Published: August 2023

Abstract
The broadly neutralizing hemagglutinin (BN-HA) stem antibodies represent an universal vaccine prospect. However, our understanding of how these antibodies interact with the influenza virus is limited by excluding other immune elements, such as complement, in our experimental systems.
Here, we show that the Fc binding protein of the complement system, C1q, grants BN-HA stem Abs a novel attachment inhibition (AI) and boosts virus neutralization (VN) activity. C1q promotes AI even if added to preformed BN-HA Ab-virion-RBC complexes, pointing at the steric nature of the phenomenon. Most probably by the same mechanism of steric hindrance, C1q also contributes to fusion inhibition. By employing a panel of engineered avidity-reverted anti-BNHA Abs we show that the C1q-mediated VN enhancement is independent of Ab avidity. We also show that C1q’s presence expands the escape viral repertoire beyond the HA stem domain. Among selected viral variants, near-RBS mutations (E156K-Sb, R224I-Ca, S145N-Ca) modulate HA avidity while causing antigenic drift. Expanding our discoveries to SARS-CoV-2, we identified non-RBD anti-SARS-CoV-2 spike Abs which exhibit C1q-VN enhancement. With an increased SARS-CoV-2 spike per viral particle amount, C1q-VN increased concomitantly. Altogether, our results emphasize the general role of C1q in Ab-mediated antiviral activity and viral evolution.
NIH/NIAID intramural funding
Evaluation of cutaneous immune response in a controlled human in vivo model of mosquito bites
Authors: Cantaert Tineke , Guerrero David , Vo Hoa Thi My , Lon Chanthap , Bohl Jennifer A , Nhik Sreynik , Chea Sophana , Man Somnang , Sreng Sokunthea , Pacheco Andrea R , Ly Sokna , Sath Rathanak , Lay Sokchea , Missé Dorothée , Huy Rekol , Leang Rithea , Kry Hok , Valenzuela Jesus G , Oliveira Fabiano , Manning Jessica E 
Published: August 2023

Abstract
Mosquito-borne viruses are a growing global threat. Initial viral inoculation occurs in the skin via the mosquito ‘bite’, eliciting immune responses that shape the establishment of infection and pathogenesis. Here we assess the cutaneous innate and adaptive immune responses to controlled Aedes aegypti feedings in humans living in Aedes-endemic areas. In this single-arm, cross- sectional interventional study (trial registration #NCT04350905), we enroll 30 healthy adult participants aged 18 to 45 years of age from Cambodia between October 2020 and January 2021. We perform 3-mm skin biopsies at baseline as well as 30 min, 4 h, and 48 h after a controlled feeding by uninfected Aedes aegypti mosquitos. The primary endpoints are measurement of changes in early and late innate responses in bitten vs unbitten skin by gene expression profiling, immunophenotyping, and cytokine profiling. The results reveal induction of neutrophil degranulation and recruitment of skin-resident den- dritic cells and M2 macrophages. As the immune reaction progresses T cell priming and regulatory pathways are upregulated along with a shift to Th2-driven responses and CD8+ T cell activation. Stimulation of participants’ bitten skin cells with Aedes aegypti salivary gland extract results in reduced pro-inflammatory cytokine production. These results identify key immune genes, cell types, and pathways in the human response to mosquito bites and can be leveraged to inform and develop novel therapeutics and vector- targeted vaccine candidates to interfere with vector-mediated disease.
Division of Intramural Research at National Institute of Allergy and Infectious Diseases at the National Institutes of Health #1ZIAAI001066-12: J.M., F.O.; Howard Hughes Medical Institute-Wellcome #208710/Z/17/Z: T.C.; French National Research Agency #ANR-17-CE15-00029: D.M.; Calmette-Yersin PhD Scholarship: D.G.
SARS-CoV-2 seroreversion is associated with a decrease in T cell functionality in children
Authors: Files Megan A , Kehoe Leanne , Adler Amanda , Englund Janet , Seshadri Chetan 
Published: August 2023

Abstract
The kinetics and durability of T cell and antibody responses to SARS-CoV-2 in children have not been well-characterized. We leveraged a longitudinal convalescent cohort of children (N = 30) aged 6 months to 20 years with PCR-confirmed (28/30) or serology-confirmed (2/30) COVID-19 in whom peripheral blood mononuclear cells (PBMC) and sera were archived at approximately 1 month, 6 months, and 12 months post-symptom onset. Nucleocapsid-specific (N) T cell functionality was evaluated utilizing intracellular flow cytometric analysis and combinatorial polyfunctionality analysis of antigen-specific T-cell subsets (COMPASS). CD4+ T cell responses to N declined over time with low cytokine production in children less than 5 years. These data suggest that cell-mediated immunity to natural SARS-CoV-2 infection in children wanes quickly, with the greatest decreases seen in children less than 5 years of age. Conversely, spike-specific (S) CD4+ T cell functionality scores remained stable up to one year after initial infection, and included signals from Th1 cytokines (IFN-γ, IL-2, TNF-α). Consistent with this, anti-S neutralizing antibody titers increased over the course of the study in children greater than 5 years, likely as a result of vaccination. Because children experience more mild disease compared to adults but can carry similar viral loads, our data suggest children may be susceptible to re-infection in the absence of vaccine-induced protection.
The proviral role of B cell-intrinsic IL-17RA signaling in the establishment of chronic gammaherpesvirus infection
Authors: Jondle Christopher Ned 
Published: August 2023

Abstract
Epstein-Barr virus (EBV) is a human specific gammaherpesvirus that establishes lifelong infection in &gt;95% of all adults and is associated with multiple cancers, including B cell lymphomas. Murine gammaherpesvirus 68 (MHV68) is a natural rodent pathogen that is genetically and biologically related to EBV and importantly provides a tractable animal model to study viral and host factors that impact chronic infection. Both of these viruses have a natural tropism for B cells and usurp B cell differentiation to drive a robust polyclonal germinal center response, which is needed to establish the latent viral reservoir in memory B cells. The factors which these viruses use to usurp the host germinal center response to establish chronic infection are not clearly defined.
Using MHV68 we discovered that global IL-17RA signaling as well as T-cell intrinsic IL-17RA signaling is proviral and supports the gammaherpesvirus-driven germinal center response needed to establish chronic infection. Loss of global and T-cell intrinsic IL-17RA signaling resulted in a significant attenuation in the germinal center response as well as viral latency and reactivation.
Given the B cell tropism of MHV68 we generated a B cell specific model of IL-17RA deficiency to understand the significance of IL-17RA signaling in virally infected cells. Loss of IL-17RA signaling in B cells during MHV68 infection resulted in an attenuated germinal center response as well as reduced viral reactivation and latency, similar to what was observed in the loss of global and T-cell intrinsic IL-17RA signaling. This indicates that IL-17RA signaling in both virally infected and uninfected cells play an important proviral role in the establishment of chronic gammaherpesvirus infection.
WMed Start up funds and an American Cancer Society Postdoctoral Award (134165-PF-19-176-01-MPC) which was used to generate the B cell specific IL-17RA deficient mice.
PD-L1 blockade enhances brain resident memory T cell function and stimulates brain to lymph node crosstalk
Authors: Musial Shawn C , Kleist Sierra A , Searles Tyler G , Degefu Hanna N , Isaacs Jordan F , Skorput Alexander G J , Rosato Pamela C 
Published: August 2023

Abstract
Resident memory T cells (TRM) are a unique subset of memory T cells that persist within non-lymphoid tissues. Previous studies have identified TRM within the brain (bTRM) after peripheral infection and vaccination in mice, with more recent appreciation in human brain tissue. While bTRM are important for protection of the CNS against reinfection, their heterogeneity at the single cell level and overall involvement in shaping the neuroimmune landscape remains unknown. Here, we defined viral-specific bTRM heterogeneity by single cell RNA sequencing and identified unique subsets dependent on local antigen encounter. These data also confirmed previous findings that bTRM express markers associated with T cell exhaustion, such as PD-1. Despite this, intracranial delivery of cognate viral peptide led to robust bTRM reactivation and initiated a cascade of immune activation and accumulation within the brain, including rapid activation of microglia, NK cells and T cells, DC maturation, and infiltration of macrophages and monocyte derived DCs. In the presence of PD-L1 blockade, despite observing higher effector molecule production from reactivated bTRM, we found no apparent difference in downstream immune activation in the brain. Interestingly, however, we found a significant increase in DC and B cell maturation in the CNS draining deep cervical lymph nodes (dcLN) only in the presence of PD-L1 blockade. These data indicate a potential unique crosstalk between bTRM and APCs in the dcLN normally suppressed by PD-1/PD-L1 signaling. These studies provide insight into brain TRM functions and potential mechanisms for strengthening immune activation that can guide immunotherapies for immunologically cold brain tumors.
Supported by grants from the NIH (K22AI148508-02, T32 AI007363)
CD8 T cell exhaustion is dynamically controlled by the chromatin regulatory factor BRD4
Authors: Mullins Genevieve N , Green Jarred M , Green William D , Milner J Justin 
Published: August 2023

Abstract
In the context of chronic viral infections and cancer, the protective potential of CD8 T lymphocytes is often dramatically blunted and characterized by a functionally exhausted cell state. T cell exhaustion contributes to pathogen persistence and can limit responsiveness to promising immunotherapy strategies. Therefore, defining the signals controlling the development and maintenance of an exhausted T cell state has critical implications for global public health. While it has become apparent that T cell exhaustion is a transcriptionally and epigenetically driven process, critical epigenetic mechanisms mediating T cell exhaustion remain unresolved. To this end, we sought to define how the ‘chromatin reader’ BRD4 controls an exhausted state in a CD8 T cell-intrinsic manner during chronic viral infection. Utilizing inducible deletion mouse models and RNAi, we found that BRD4 is a critical regulator of T cell differentiation and function. BRD4 was essential for driving a terminally exhausted CD8 T cell state. Mechanistically, BRD4 was found to bind near and modulate expression of key genes that influence T cell differentiation and exhaustion. Finally, small molecule inhibition of BRD4 was seen to reverse a terminally exhausted cell state. These findings provide insights into the epigenetic underpinnings of T cell exhaustion and have important implications for enhancing immunotherapy efficacy.
Supported by a CGIBD pilot award and grant from NCI (R00CA234430).
Brain-resident memory cells (bTRM) and virus reactivation
Authors: Gupta Priyanka , Hu Shuxian , Nomura Wen Sheng , Lokensgard James R 
Published: August 2023

Abstract

Background
Neuroimmune responses terminate MCMV acute infection, however, a subset of neurons still harbor latent viral genomes. Factors regulating viral reactivation remain to be elucidated.

Methods
Using RNAscope, IE1 nucleic acid was detected within brains at D5 and D30 p.i. Using real-time RT-PCR, we assessed expression of IE1, E1, and gB transcripts. Using multi-color flow cytometry, we assessed depletion of bTRM following icv injection of either α-CD8 Ab or α-CD103-sap. Using luciferase-expressing transgenic mice, we longitudinally assessed reactivation of cre-MCMV after T-cell depletion using live small animal imaging. Explant assay was employed to study the role of bTRM in reactivation. Using Nanostring, we identified changes following bTRM-depletion.

Results
Brain infection was demonstrated by X-gal staining as well as IE1 staining using RNAscope at 5 d p.i. After 30 d p.i., the virus established latency, as indicated by absence of transcripts (IE1, E1, and gB). After establishment, we injected either α-CD8 Ab or α-CD103-sap into the brain and showed 90–95% T-cell depletion. We infected mice with cre-MCMV, which expresses Cre recombinase. We observed enhanced imaging signals indicative of IE promoter activity in depleted animals. Surprisingly, we efficiently recovered virus from untreated mice, but not from those depleted of bTRM. Furthermore, on Nanostring analysis, we identified gpnmband hmox1, upregulated 11.48- and 6.7-fold following bTRM depletion.

Conclusion
When we depleted bTRM, there was transient IE expression, sufficient to activate surveying microglia. This eventually resulted in a tissue-wide anti-viral state. These data provide new insights into the role of bTRM in controlling reactivation.

This project was supported by award numbers NS-038836 from the National Institute of Neurological Disorders and Stroke
TLR3 Signaling is Required for Robust Extrafollicular B Cell Response (EF) in Influenza A/PR/8 Infection
Authors: Keller Emma J , Lam Jonathan , Baumgarth Nicole 
Published: August 2023

Abstract
Following influenza A virus (IAV) infection B cells rapidly proliferate and differentiate into plasma cells (PCs) in extrafollicular foci (EF) within mediastinal lymph nodes (medLN), resulting in protective antibody secretion. We had shown that co-expression of both TLR adaptor proteins, TRIF and MyD88, is required for robust EF responses. Only two TLRs, TLR3 and 4, signal using TRIF. As shown previously TLR3 and 7, but not TLR4, expression were upregulated by medLN B cells within 2 days post infection (dpi) in a Type-I IFN-dependent manner, suggesting that TLR3 might utilize TRIF in B cells during IAV infection. To test this we generated MyD88 × TLR3 double-deficient (DKO) mice. Flow cytometry on MedLN at 7 dpi showed significantly reduced EF B cells (CD19lo B220lo CD38lo CD24hi) and CD138+plasma cells (PCs), including IAV-specific PCs, as well as reduced serum IAV-specific IgG and IgG2C in DKO compared to C57BL/6 or single- MyD88 and TLR3 deficient mice. IAV infection of mixed bone marrow chimeras indicated that the TLR3-TRIF axis contributes to EF formation at least in part in a B cell-intrinsic manner. In vitro stimulation of B cells with the TLR3 agonist, Poly: IC, caused expression of several activation/costimulatory molecules but did not induce proliferation. Together, the data suggest that TLR3-mediated B cell is a non-redundant driver of rapid protective antibody responses.
Supported by NIH/NIAID R01AI117890 (NB) and NIH T32 HL007013-40 (JHL and EJK).
LPAR5-Mediated Regulation of CD8 T Cell Immunity During Chronic Viral Infections
Authors: D’Antonio Marc , Ware Brian C , Turner Jacqueline A , Davenport Bennett J , Morrison Thomas E , Torres Raul M 
Published: August 2023

Abstract
Persistent viral infections such as Human Immunodeficiency Virus (HIV), Hepatitis B and C Viruses (HBV & HCV), and Epstein Barr Virus (EBV) result in high mortality rates, tremendous healthcare costs, and limit global life expectancies. Paramount to establishing and maintaining chronic infections, viruses must evade or suppress T cell-mediated immunity, often through promoting the generation of dysfunctional or “exhausted” CD8 T cells. Although there are considerable research efforts investigating mechanisms of T cell exhaustion, further work is necessary to identify and characterize therapeutically targetable regulators of exhaustion programming. Work from our lab has focused on the ability of the bioactive lipid, lysophosphatidic acid (LPA), to regulate CD8 T cell function through LPA receptor 5 (LPAR5) signaling. Importantly, significantly elevated levels of LPA have been identified in chronic viral infections and cancers. We previously demonstrated that activation of LPAR5 on CD8 T cells during TCR engagement suppresses downstream signaling events. Since TCR-induced transcriptional networks regulate T cell exhaustion programming, we hypothesize that LPA-mediated changes in gene expression during chronic infections promotes the generation of dysfunctional CD8 T cells. To investigate the role of LPA in the differentiation of exhausted CD8 T cells, we utilized the LCMV Clone 13 infection model. We postulate that the elevated levels of LPA identified in persistent infections and our initial findings investigating LPAR5 signaling in CD8 T cells provide strong a rationale to evaluate LPA signaling as a previously unexplored pathway by which chronic viruses promote T cell exhaustion to establish and maintain persistence.
RO1AI143261-02 T32-AI07405
CD4 T cell deficiency narrows virus-neutralizing IgG coverage for Polyomavirus and selects for antibody-escape variants
Authors: Ayers Katelyn Nicole , Lauver Matthew D , Lukacher Aron E 
Published: August 2023

Abstract
CD4 T cell deficiencies predispose patients to progressive multifocal leukoencephalopathy (PML), a brain disease caused by JC polyomavirus (JCPyV). PML is linked to immunomodulatory therapies that preferentially lower CD4 T cells in the CSF (natalizumab); but how CD4 T cells control JCPyV is undefined. “Blind spots” in the ability to neutralize JCPyV variants with mutations in the VP1 capsid protein were described in PML patients. We recently reported that a VP1 mAb selects for VP1-mutant escape variants both in vitro and in vivo; some of these variant viruses are neurovirulent. We hypothesized that alterations in the Ab response due to CD4 T cell insufficiency underlie emergence of Ab-escape mouse polyomavirus (MuPyV) variants. T-cell independent (TI) VP1-specific IgG (via anti-CD4 mAb depletion, CD40L blockade, MHCII KO mice, IL21R KO mice) neutralizes MuPyV but has reduced titer and avidity than anti-VP1 IgGs in CD4 T cell-sufficient mice. Serial passaging of MuPyV in vitro with sera from TI mice selected an Ab-escape VP1 mutant containing amino acid deletions at residue 145–146 in an external loop of VP1 (MuPyV.145–146). In contrast to sera from healthy MuPyV-infected mice, TI sera failed to neutralize MuPyV.145–146. Depletion of CD4 T cells during persistent MuPyV infection, as a model of acquired CD4 T cell insufficiency (i.e. onset of immunomodulatory mAbs) via anti-CD4 mAb depletion, CD40L blockade, and anti-CD20 mAb B cell depletion also reduced anti-VP1 IgG titer and avidity. Ongoing studies seek to determine if a similar loss in recognition of the 145–146 VP1 epitope occurs. Our data shows that a narrowed antiviral IgG response due to CD4 T cell deficiency is a critical antecedent for outgrowth of Ab-escape PyV VP1 mutant viruses.
Supported by grants from the NIH (5R01NS088367, 5R01NS092662, and R35NS127217) (AEL) Judy S. Finkelstein Memorial Award (KNA) T32 CA06395 (KNA)
Intermediate levels of preexisting protective antibody allow priming of protective T cell immunity against Influenza
Authors: Mansoor Mishfak Abdullah Mohamed , Malavet Valeria Flores , Ng Terry , Arvelo Andrea C , Strutt Tara M 
Published: August 2023

Abstract
Overcoming interfering impacts of preexisting immunity to generate universally protective influenza A virus (IAV)-specific T cell immunity through vaccination is a high priority. Here, we passively transfer varied amounts of H1N1-IAV-specific immune serum prior to H1N1-IAV infection to determine how different levels of preexisting Ab influence the generation and protective potential of heterosubtypic T cell responses in a murine model. Surprisingly, IAV nucleoprotein (NP)-specific CD4 and CD8 T cell responses are readily detected in infected recipients of IAV-specific immune serum regardless of the amount transferred. When compared to responses in control groups and recipients of low and intermediate levels of convalescent serum, NP-specific T cell responses in recipients of high levels of IAV-specific serum, which prevent overt weight loss and reduce peak viral titers in the lungs, are, however, markedly reduced. While detectable at priming, this response recalls poorly and is unable to mediate protection against a lethal heterotypic (H3N2) virus challenge at later memory timepoints. A similar failure to generate protective heterosubtypic T cell immunity during IAV priming is seen in offspring of IAV-primed mothers that naturally receive high titers of IAV-specific Ab through maternal transfer. Our findings support that priming of protective heterosubtypic T cell responses can occur in the presence of intermediate levels of preexisting Ab. These results have high relevance to vaccine approaches aiming to incorporate and evaluate cellular and humoral immunity against IAV and other viral pathogens against which T cells can protect against variants escaping Ab-mediated protection.
Supported grants from NIH (RO1 AI165406) Startup funds from the University of Central Florida foundation