bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen-specific reactivation of brain tissue resident memory CD8 T cells directly induces severe neuroinflammation and blood-brain-barrier disruption
Authors: Ayasoufi Katayoun , Wolf Delaney M , Jin Fang , Bamkole Michael A , Tritz Zachariah , Maynes Mark A , Pfaller Christian K , Hansen Michael , Fain Cori E , Johnson Aaron J 
Published: August 2023

Abstract
Intracranial infection with neurotropic Theiler’s Murine Encephalomyelitis Virus induces robust generation of brain TRMs against the immunodominant antigen, VP2121–130, following viral clearance in C57BL/6 mice. While the presence of TRMs in the brain is documented, neurological consequences of TRM reactivation and their causal role in neuropathology remain understudied. We disabled peripheral CD8 T cells via anti CD8 depleting strategies and FTY720 treatment to determine the causal link between brain TRM reactivation and neuropathology. We depleted peripheral T cells and then administrated VP2 peptide IV to reactivate TRMs 60–200 days post infection as this elegant technique isolates responses of brain TRMs away from other branches of memory. We used state-of-the-art flow cytometry and MRI analysis to evaluate neurological consequences of TRM reactivation. TRM reactivation induced severe neuroinflammation in the brain as evident by infiltration of myeloid cells and blasting of T cells. MRI detected gadolinium leakage marking severe blood-brain-barrier (BBB) disruption when brain TRMs were reactivated. Depletion of peripheral CD8 T cells with low-dose anti CD8 antibodies or their sequestration via FTY720 did not alter neuroinflammation indicating brain TRM reactivation causally initiates neuropathology. Confirming this, tissue depletion of all TRMs in the brain using high-dose anti CD8 antibodies prevented both neuroinflammation and neuropathology. Hence, TRM reactivation causes severe neuroinflammation and BBB disruption from within the brain independently of peripheral T cells. Targeting brain TRM reactivation is a novel potential therapeutic for patients with many acute and chronic neurological diseases.
Supported by grants from NIH (K99NS117799-01A1 (KA), R01NS103212 (AJJ), and RF1NS122174(AJJ)
Persistent CD4 T cell functional deficits in individuals recovered from prolonged symptomatic SARS-CoV-2 infection
Authors: Kovats Susan , Lawrence Christina , Turner Sean , Pezant Nathan , Redinger Nancy , Guthridge Carla , Smith Ken , Guthridge Joel M , James Judith A , Farris A Darise 
Published: August 2023

Abstract
We assessed phenotypic changes in CD4+ T cells in 17 individuals (male and female, age 26–71, not hospitalized) after recovery from moderate SARS-CoV-2 infection. A subset of 5 individuals with protracted symptom duration showed marked downregulation of CD4 on CD3+CD8− T cells and a poor response to TCR stimulation with SEB, as judged by failure to upregulate activation markers CD134, CD25 and CD69. This defective response (DR) group included 3 subjects sampled &lt;30 days and 2 sampled &gt;150 days post-recovery. In longitudinal samples obtained 3–12 months later, 4 of 5 individuals harbored T cells showing a recovered response (RR), with CD4 levels comparable to normal response (NR) healthy controls. One individual did not show a recovered response until 10 mo later. Levels of anti-S1 IgG did not correlate with the CD4 defect. Selected plasma cytokines (IL-1RA, APRIL, VEGF) elevated in the DR group correlated with low CD4 levels. The SEB activation program, defined as genes differentially expressed (DE) between paired unstimulated and stimulated CD3+CD8− T cells, showed a &gt;50% reduction in the number of DE genes in the DR group compared to the RR and NR groups. Upstream driver analysis of genes uniquely DE in the NR and RR groups, representing a recovered/normal activation program, showed strongly reduced influence of VEGF. Conversely, similar analysis of genes uniquely DE in the DR group showed reduced influence of TCR signaling. In sum, recovery from prolonged symptomatic Covid-19 is often associated with a global CD4+ T cell response defect, defined by low surface CD4 and defective T cell activation at the transcriptional level, and correlating with elevated cytokines such as VEGF associated with severe or long Covid-19.
Supported by NIH U19 AI062629
HIV-1 Tat impairs the establishment and maintenance of latency in a quiescent T cell line model of HIV infection
Authors: Gomez-Rivera Francisco , Terry Valerie H , Virgilio Maria C , Collins Kathleen L 
Published: August 2023

Abstract
Human Immunodeficiency Virus (HIV) persists as a transcriptionally silent, latent provirus despite optimal therapy. Latently infected cells avoid immune detection and viral cytopathic effects becoming a long-lived reservoir of HIV. To elucidate factors responsible for the establishment of latency, our lab developed two novel HIV-1 reporter constructs (89.6 VT1 and 454 VT2). Studies using these reporters demonstrated that the multiplicity of infection (MOI) (the ratio of viral particles to cells) strongly correlated with the proportion of active versus latent infection in a “quiescent” T cell line. This observation suggested the hypothesis that at low viral inoculum, the availability of a viral factor, such as the HIV transactivator of transcription (Tat), was limiting and affected the likelihood that active versus latent infection was established. To test this, we (1) examined relative tat levels in reporter viruses that established different proportions of latent versus active infection (2) measured active versus latent infection in a cell line that constitutively overexpressed tat and (3) modified the dual reporter 89.6 VT1 to overexpress tat after an IRES element. In every case, higher tat levels correlated with increased active infection and a reduction in dependency of active infection on the amount of inoculum. Ongoing studies will test the extent to which Tat levels vary in native HIV proviral genomes. These studies provide insight into the molecular mechanisms that govern latency establishment at high versus low viral infection conditions and may shed light on new approaches to eradicate latently infected cells.
Supported by grants from NIH/ NIAID (R01 AI148084 S1)
Influenza virus infection modulates expression of the anti-inflammatory mucin 1 in both epithelial and immune cells
Authors: Abdelhamid Leila , Scull Margaret Adele 
Published: August 2023

Abstract
Cell-associated mucin 1(MUC1/Muc1) is a component of the mucus barrier in the respiratory tract that acts as a physical barrier and signaling molecule. Our prior work shows that MUC1 expression is increased during influenza virus (IAV) infection in human airway epithelial (HAE) cultures in vitro. Here we further detail MUC1 expression patterns and report that IAV-induced cytokines, including type I interferons (IFNs), trigger the expression of a low-molecular-weight form of MUC1 which localizes to the cytoplasm and nucleus, and is expressed in different epithelial cell types. Further, IFN-driven changes in the cellular composition of HAE toward a more secretory phenotype require MUC1, suggesting that MUC1 plays an important role in shaping the epithelial response during viral infection. Using a mouse model of IAV infection, we confirmed the upregulation of Muc1 throughout the epithelium in vivoand observed altered Muc1 levels in lung immune cells. Specifically, Muc1 was upregulated in interstitial macrophages but downregulated in antigen-presenting cells (APCs) including alveolar macrophages and dendritic cells as early as 2 days post-infection (dpi). By 5 dpi, Muc1 was significantly upregulated in various T cell subsets and their effector counterparts including CD4+, CD8+, and double-negative effector T cells. We also found a negative correlation between Muc1 levels in APCs and the expansion of effector T cell populations, supporting the putative immunoregulatory roles of MUC1/Muc1. Our ongoing work further explores the impact of Muc1 expression in specific cellular subsets on the immune response and IAV pathogenesis.
This work was supported by the National Heart, Lung, and Blood Institute (R01HL151840, to MAS)
CD40-dependent mechanism of virus control in a mouse model of HBV infection
Authors: Bailey Jacob T , Rexhouse Catherine , Moshkani Safiehkhatoon , Robek Michael D 
Published: August 2023

Abstract
An estimated 296 million people worldwide currently live with chronic hepatitis B virus (HBV) infection. Up to 90% of newborns and 30% of children with acute hepatitis B develop chronic infections, causing lifelong complications including liver cirrhosis and cancer. HBV persistence is a consequence of T and B cell dysfunction, so immunotherapy has been proposed as a means of HBV control. TNF receptor superfamily member CD40 has shown therapeutic value in overriding T cell exhaustion and inducing lymphocyte responses in solid tumors and viral infections. To determine the efficacy of CD40 targeting in generating HBV-resolving immune responses, mice were simultaneously transduced with adeno-associated virus encoding the HBV genome (AAV-HBV) and treated with the agonistic CD40 antibody FGK4.5 to activate CD40 signaling. AAV-HBV mice receiving FGK4.5 saw a transient reduction in HBV as determined by serum antigen analysis, while antigen levels in CD4-depleted mice treated with FGK4.5 became undetectable over seven weeks. HBV control was strongly associated with the generation of HBV-specific CD8+ T cells, increased serum ALT, and elevated expression of intrahepatic CD8+ T cell-related genes. Histological analysis of the liver revealed loss of hepatitis B core antigen-positive hepatocytes and increased inflammatory foci. Neither Treg cell depletion nor checkpoint inhibition in CD4-replete mice affected HBV control. Lastly, CD40 activation in CD4-depleted chronically infected mice also reduced both serum antigenemia and liver HBV RNA. Taken together, these results implicate a critical role of CD4+ T cells in maintaining HBV immune tolerance and further suggest CD40 as a potential therapeutic target for chronic HBV infection.
Supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award numbers R01AI124006 and R01AI148354. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
NAC1 constrains CD4+ T cell memory formation through the ROCK1-mediated pathway
Authors: Wang Liqing , Song Jianxun 
Published: August 2023

Abstract
Nucleus accumbens-associated protein 1 (NAC1) is a transcriptional co-factor that has been extensively investigated in cancer biology. Our recent studies indicate that NAC1 can modulate the functional activity of regulatory T cells and tumoral expression of NAC1 restrains antitumor immunity. However, little is known about its regulation of memory T cells. In the current study, we analyzed CD4+ T cells from wild type (WT) and NAC1-decificient (−/−) mice and used the vaccinia virus (VACV) as the tool to investigate the precise role and mechanism of NAC1 in controlling CD4+ T cell memory. In vitro, we identified that NAC1 is essential for T cell metabolism, including both glycolysis and oxidative phosphorylation, which positively modulates CD4+ T cell survival. We also revealed that NAC1 deficiency has an interruption of the AMPK-mTOR pathway, resulting in decreased glycolysis and defective autophagy of CD4+ T cells. Mechanically, loss of NAC1 downregulates ROCK1 expression and reduces the phosphorylation and stabilization of BECLIN1. When overexpressing ROCK1 in NAC1−/− CD4+ T cells, both the defective autophagy and the interrupted AMPK-mTOR pathway were restored. In vivo, when i.p. challenged with VACV, NAC1−/− mice had improved VACV-specific CD4+ memory T cell formation at 35 days compared with WT mice. Furthermore, in adoptively transferred experiments when overexpressing ROCK1 of NAC1−/− CD4+ T cells (Thy1.2+) in congenic hosts (Thy1.1+), the increased memory T cell formation of NAC1−/− CD4+ T cells was reverted to a normal WT level. Conclusively, we define that NAC1 acts as a suppressor of CD4+ T cell memory formation through the ROCK1-mediated pathway, and targeting NAC1 may be adapted to promote memory CD4+ T cell development.
Asymmetric Cross-Protection is Elicited by Distinct Influenza B Lineages
Authors: Page Caroline Katherine , Shepard Justin , Ray Sean , Lorton Ana T , Rowe Dawne , Tompkins Stephen Mark 
Published: August 2023

Abstract
The immune response to influenza B virus (IBV) infection is understudied compared to influenza A virus (IAV), despite IBV accounting for 20% of influenza-related hospitalizations annually. Influenza B was first isolated in the 1940s and subsequently diverged into two distinct lineages, Victoria (B/Vic) and Yamagata (B/Yam), defined by changes in the hemagglutinin (HA) and basic polymerase (PB1 and PB2) gene segments. The two IBV lineages are antigenically distinct, resulting in the development of influenza vaccines containing both B/Vic and B/Yam in addition to H1N1 and H3N2 IAVs. Differential epidemiologic dynamics of the IBV lineages and the recent proposed extinction of B/Yam suggests the lineages do not elicit equivalent immunity. Human studies have shown B/Yam-infected persons are susceptible to reinfection with the same lineage virus, suggesting B/Yam-elicited immunity is insufficient compared to B/Vic-elicited immunity, which prevents homotypic reinfection. Here we established a murine model of contemporary IBV infection that supports observational studies. We demonstrated immune responses elicited by B/Yam infection is insufficient to protect against a heterolineal infection (B/Vic challenge). Conversely, B/Vic-elicited immunity protected against homologous and heterolineal (B/Yam) challenge. We assessed virus-specific serum antibody (Ab) responses following primary infection and challenge. Serological data suggest B/Yam infection failed to elicit cross-reactive Ab, allowing B/Vic infection, while B/Vic elicited serum Ab against both lineages. Ongoing studies seek to define the virus-specific B-cell response to B/Yam and B/Vic infection and to confirm these results in a ferret model of IBV infection.
Supported by grants from NIH Contract 75N93021C00018
Profiling of the antibody response to viral and bacterial antigens and its correlations with time-to-hospital discharge: Covacta and Mariposa study
Authors: Shrivastava Divya , Budde Petra Ilse , Onabajo Olusegun , Bräutigam Manuel , Zucht Hans-Dieter , McBride Jacqueline , Bauer Rebecca , Chandler Scott , Kuebler Peter 
Published: August 2023

Abstract
In this study the role of the humoral response to viral and bacterial antigens in hospitalised patients with severe COVID-19 and its association with clinical endpoint time-to-hospital discharge (TTHD) was investigated. Here, we analysed the antibody (Ab) response to SARS-CoV-2 structural and non structural proteins, other influenza(s) and bacterial proteins using bead-based protein and peptide arrays comprising different viral epitopes. In total, 459 pre-treatment serum samples from hospitalised COVID-19 patients enrolled in the COVACTA and MARIPOSA clinical trials were analysed to identify Ab reactivity to protein antigens and linear epitopes associated with TTHD. Overall we found that most patients had IgG-Abs to SARS-CoV-2 S protein (89%), N protein (90%) and RBD domain (95%). Three major epitopes of the S protein were identified which map to the C-terminus of the RBD, TMPRSS2 cleavage site and fusion peptide 1, and close to the heptad repeat 2 domain. These epitopes could be further researched to understand the immunity to COVID-19 and how it affects outcomes.
Abs binding to several peptides mapping to the RBD C-terminus and N-terminal to heptad repeat 2 were associated with longer TTHD. Abs to an epitope mapping to the intracellular domain of S protein and to the RNA-binding domain of the N protein showed the strongest association with longer TTHD. Abs to seasonal corona viruses and influenza A & B, S. aureus, and rhinovirus were associated with shorter TTHD. To conclude, epitope-specific multiplexed Ab profiling of anti-SARS-CoV-2 response may potentially be used to predict clinical outcome. Pre-existing humoral immunity to seasonal corona viruses and influenza may also confer some protective effects against COVID-19
The metabolic role of gut dysbiosis in altered T cell responses to influenza virus infection
Authors: Cheetham Susana , Meza-Perez Selene , Sanchez Aaron Silva , Randall Troy 
Published: August 2023

Abstract
Commensal gut microbiota modulates protective immune responses to viral infections at extra-intestinal sites, including the lungs. Gut dysbiosis induced by broad-spectrum antibiotic treatment appears to alter adaptive immunity to influenza infection (IAV/PR8). However, the mechanism by which microbial metabolism influences immune responses across the gut-lung axis remains unclear. Here, we used flow cytometric analysis to investigate T cell responses to IAV in specific pathogen free (SPF), Altered Schaedler flora (ASF) and germ-free mice models. We show that, compared to SPF mice, ASF and germ-free mice have significantly reduced levels of regulatory T cells (Tregs) and virus specific cytotoxic CD4 and CD8 T cells at 10 days post infection. Further analysis of microbial mediators in the peripheral blood of these mice revealed significantly increased levels of L-arginine in the serum of ASF and germ-free mice compared to SPF mice. We noted that, germ-free and ASF mice lack bacteria that metabolize dietary amino acids, including L-arginine, regulating its increased availability in the peripheral blood of these mice. To investigate the role of L-arginine as a microbial mediator of reduced T cell responses to IAV, we supplemented L-arginine or administered neomycin (to induce selective disruption of arginine metabolizing bacteria) to separate cohorts of SPF mice. We observed altered cytotoxic and effector T cell responses at 10 days post infection in the experimental groups, however, Tregs were not significantly affected. Our data suggests that selective dysbiosis may increase L-arginine levels in the serum of SPF mice which may directly affect virus specific effector T cell responses in the lung mucosa.
RSV-specific T cell epitope presentation in the respiratory tract differs between adults and neonates as revealed by a novel T cell proliferation assay
Authors: Nhan Paula , DaMata Jarina P , Lu Zhongyan , Ennis Katherine H E , Malloy Allison M W 
Published: August 2023

Abstract
Respiratory syncytial virus (RSV) invades the respiratory epithelium and provokes severe symptoms in young children leading to infant mortality. CD8 tissue resident memory (TRM) cells are associated with protection in adults against RSV, but are poorly established in neonatal mice consequent to primary infection. We hypothesized that antigen presentation contributes to age-dependent TRM establishment, thus we sought to define antigen kinetics in RSV-infected adult and neonatal mice.
CB6F1/J adult and neonatal mice were infected with RSV and lung tissue were isolated over the course of acute and convalescent infection. Single cell lung suspension was co-cultured in vitro with RSV Kd M282–90 (M2) or Db M187–195 (M) epitope-specific T cells isolated from CD8 T cell receptor (TCR) transgenic mice. T cells were stained with carboxyfluorescein succinimidyl ester (CFSE) to quantify proliferative response 48 hours post-incubation at 37°C via flow cytometry.
From lung tissue isolated at 7 days post infection (dpi), M and M2-specific CD8 T cells proliferated in response to co-culture; however, higher rates were induced by neonatal lung tissue primarily by M-specific T cells. By 8 and 9 dpi, proliferation induced by isolated neonatal lung continued while proliferation induced by adult lung tissue was not quantifiable by our assay.
Our findings suggest antigen availability in neonates exceeds that of adults and is age and epitope-dependent. These discoveries indicate that antigen accessibility does not independently correspond with the magnitude of the T cell response in early life. Exploring the inflammatory contributions to RSV-specific T cell defenses is required as this may aid in vaccine design and understanding disease pathogenesis.
Supported by grant from NIH R01-AI154619.
Single cell transcriptomics identify AHR and CD9 as markers of CD14+ atypical B cells
Authors: Blevins Lance K , Khan Isha O , Crawford Robert B , Kaminski Norbert E 
Published: August 2023

Abstract
B lymphocytes are adaptive immune cells responsible for the production of antigen specific antibodies and the release of pro- and anti-inflammatory cytokines. Pro-inflammatory B cells, often termed atypical B cells (at B cell) are a heterogenous population of B lymphocytes associated with aging, infection, and autoimmunity. Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor important for xenobiotic metabolism. However, AHR is heavily implicated in immune cell differentiation as a regulator of cell fate decisions. at B cells are believed to represent an alternative B cell lineage but the role of AHR in at B cells is not known. We have reported that human, primary CD5+ innate-like B cells (ILB) are preferentially sensitive to modulation by AHR-activation compared to CD5− B cells. CD5+ ILB are a heterogenous population of B cells enriched in IgM memory B cells, B1 B cells, marginal zone B cells, regulatory B cells, and at B cells. We used Single cell transcriptomics to elucidate AHR expression in human naïve, circulating CD19+ B cells isolated directly from PBMC and enriched for CD5 protein. We found that AHR expression correlated with expression of CD14 and were enriched in a myeloid gene signature. These results were validated in isolated CD9+ B cells and PBMC. Further, CD14 expressing B cells were enriched in CD9 isolated cells and expressed higher CD11c and Tbet and lower IgD, markers of atypical B cells, compared to CD9− B cells. These data suggest that CD9 and AHR are putative markers of CD14+ at B cells. (Supported by NIH grant P42ES004911)
Supported by NIH grant P42ES004911
Effects of IL-9 on TRAF3-deficient B cell activation
Authors: Jung Jaeyong , Gokhale Samantha , Victor Eton , Tsai Jemmie , Spirollari Eris , Matracz Brygida , Takatsuka Shogo , Kitamura Daisuke , Xie Ping 
Published: August 2023

Abstract
The pleiotropic cytokine interleukin-9 (IL-9) signals to target cells by binding to a heterodimeric receptor consisting of the IL-9 receptor (IL-9R) and the common subunit γ chain. In the present study, we found that the expression of IL-9R was strikingly up-regulated in mouse naïve follicular B cells genetically deficient in TRAF3, a critical regulator of B cell survival and function. The highly up-regulated IL-9R on Traf3−/− follicular B cells conferred responsiveness to IL-9, including IgM production and STAT3 phosphorylation. Interestingly, IL-9 significantly enhanced class switch recombination to IgG1 induced by B cell antigen receptor crosslinking plus IL-4 in Traf3−/− B cells but not in wild type B cells. Blocking the JAK-STAT3 pathway abrogated the effects of IL-9 on Traf3−/− B cells. Our study thus revealed a novel pathway that TRAF3 suppresses B cell activation and Ig isotype switching by inhibiting IL-9R-JAK-STAT3 signaling. Our findings provide new insights into the TRAF3-IL-9R axis in B cell function and have significant implications for the understanding and treatment of a variety of human diseases involving aberrant B cell activation.
This study was supported by the National Institutes of Health grants R01 CA158402 (P. Xie) and R21 AI128264 (P. Xie), the Department of Defense grant W81XWH-13-1-0242 (P. Xie), and a Busch Biomedical Grant (P. Xie). FACS analyses were supported by the Flow Cytometry Core Facility with funding from NCI-CCSG P30CA072720.