bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of extrinsic pathway mediators in CD8+CD38+ T cells of healthy donors stimulated with Mycobacterium tuberculosis antigens (99.20)
Authors: Alvarez-Jimenez Violeta , Serafin-Lopez Jeanet , Estrada-Parra Sergio , Estrada-García Iris Elvira , Sandoval-Montes Claudia 
Published: January 2023

Abstract
CD38 is expressed in human T cells during early stages of activation and differentiation and can be used as a marker of prognosis for HIV. Currently, CD38 has raised interest since it has been found increased in patients with tuberculosis, however when the active phase is solved a decrease of CD38 in CD8 T lymphocytes is observed. Here we evaluated and determined the role of CD38 in human CD8 T lymphocytes stimulated with M. tuberculosis H37Rv soluble extracts (MTSE) and delipidized MTSE (dMTSE) in vitro. For this purpose, PBMC from healthy donors were incubated with PMA-ionomicyne, media, MTSE or dMTSE. After cultured, cells were harvested and stained with monoclonal antibodies conjugated to different fluorochromes. After kinetics experiments were performed and the expression of perforin, granzyme A, IFN-γ and CD38 in T CD8 cells was determined by flow cytometry. Expression of IFN-γ and perforin was statistically higher in T CD8+CD38+ in comparison with T CD8+CD38-. Remarkably, CD8+CD38+ T cells showed an increased cytotoxicity against macrophages pulsed with MTSE. These results suggest that the population of T CD8+ lymphocytes might have an effector functions in Ag specific dependance on CD38. This is the first report linking CTL activity to the CD38 molecule in tuberculosis.
Host immunity and pathogen genotype contribute to disaccharidase impairment following gut infection in vivo (99.23)
Authors: Solaymani-Mohammadi Shahram , Singer Steven 
Published: January 2023

Abstract
Using a mouse model of infection with the GS strain of the human parasite Giardia duodenalis, we examined the role of host immunity and pathogen genotype in inducing disaccharidase deficiency. The levels of sucrase, maltase, and lactase decreased in the small intestines of C57BL/6J mice at the peak of infection. Lack of functional adaptive immunity in SCID mice resulted in increased parasite burdens, failure to eliminate the infection and no impairment of intestinal enzymes. Experiments using beta2microglonbulin knockout animals implicated CD8+ T cells as mediating disaccharidase deficiency. Interestingly, wild-type mice infected with the WB strain of G. duodenalis, did not exhibit decreased disaccharidase levels. These strains are prototypes of two genetically distinct assemblages within the species G. duodenalis, suggesting that the assemblages may be distinct in causing disaccharidase deficiency in human infections. Analysis of in vitro cytokine production by CD4+ T cells in response to pathogen extracts showed similar production of IL-4, IL-10, IL-13, IL-22, TNF-alpha and IFN-gamma following infection with IFN-gamma being the dominant cytokine for both parasite strains. These findings reveal the significance of both host and pathogen factors as key players in determining the outcome of murine infections, and may explain why some human patients exhibit malnutrition syndrome while others do not.
Identification of novel, biologically distinct T cell responses to chronic viral infection by unsupervised analysis of gene expression profiles of hepatitis C-specific CD8+ T cells. (105.12)
Authors: Gupta Prakash , Wolski David , Alexe Gabriela , Lauer Georg , Haining William 
Published: January 2023

Abstract
During the course of a viral infection, CD8+ T cells responding to the virus differentiate into heterogeneous subpopulations of antigen (ag)-specific cells. Characterizing this phenotypic heterogeneity is limited by the number and choice of molecules that can be assayed on tetramer+ CD8+ T cells by flow cytometry. We studied genome-wide expression profiles of tetramer-sorted ag-specific CD8+ T cells from 27 Hepatitis C virus (HCV) infected patients to identify new molecular subtypes of HCV-specific T cell responses. Unsupervised analysis of HCV-specific profiles by a novel clustering algorithm revealed two distinct subclasses of T cell response among the patients. These molecular phenotypes did not simply represent known differentiation states (e.g. exhaustion or memory), but were instead related to critical biological differences: HCV-specific T cells in subclass 2 showed significant upregulation of proliferation, metabolism and RNA processing genes, suggesting increased T cell fitness. Clinically, patients in this subclass controlled viral load significantly better than those in subclass 1. Subclass-specific markers associated with poor outcome were validated on HCV-specific T cells by flow-cytometry. We demonstrate that unsupervised analysis of genome-wide expression profiles of ag-specific CD8 T cells in humans can identify new biological types of T cell response and novel biomarkers of clinical outcome in chronic viral infection.
CD8 T cell memory precursors are found in bone marrow upon activation after acute LCMV infection (105.14)
Authors: Romagnoli Pablo , Premenko-Lanier Mary , Loria Gilbert , Lefrancois Leo , Altman John 
Published: January 2023

Abstract
The amount and quality of CD8 T cell memory generated in response to an acute infection with an intracellular pathogen is influenced by the signals present in the tissues in which CD8 T cells are activated. Here, we investigated if location dictates the phenotype and functional properties of CD8 T cells responding to acute lymphocytic choriomeningitis virus (LCMV) infection in different lymphoid tissues. First, we show that CD8 T cells isolated 3 days post infection (p.i.) from bone marrow (BM) displayed a memory precursor phenotype, CD62LloCD25loLy6Chi different to the phenotype observed in LCMV-specific CD8 T cells from spleen or peripheral lymph nodes (PLN). Second, we show that T-bet, a T-box transcription factor found predominantly in terminally differentiated effector CD8 T cells, is almost absent in LCMV-specific CD8 T cells from BM in contrast to the high T-bet expression found on LCMV-specific CD8 T cells from PLN and spleen. Differences in T-bet are also detected after acute infection with vesicular stomatitis virus and L. monocytogenes. Finally, we find that CD8 T cells from BM recall better upon secondary challenge when compared to CD8 T cells from spleen or PLN. These findings strongly suggest that CD8 T cell memory precursors can arise in BM early after acute infection with an intracellular pathogen and further investigation is needed to define the environmental signals influencing CD8 T cell memory differentiation.
Partial clearance of a hepatotropic virus infection in HLA class I and II double transgenic human immune system mice (105.19)
Authors: Billerbeck Eva , Horwitz Joshua , Labitt Rachael , Budell William , Rice Charles , Ploss Alexander 
Published: January 2023

Abstract
Humanized mice have emerged as a promising model to study human immunity in vivo. While they are susceptible to many human lymphotropic pathogens, immune responses to infection remain functionally impaired in these mice. It has been shown that the expression of HLA class I or II improves human immunity in this model. However, little is known about the extent of functional human immune responses in non-lymphoid tissues, such as in the liver, and the role of HLA expression in this context. In this study, we analyzed human antiviral immune responses in humanized mice during a hepatotropic adenovirus infection. Specifically, we compared human immune responses of conventional humanized NSG (NOD-SCID IL2RγNULL) mice to those of a novel NSG strain transgenic for HLA-A*0201 and a chimeric HLA-DR*0101. Humanized mice were generated by transplantation of human CD34+ hematopoietic stem cells (HSC) into newborn, sublethally irradiated mice. The development of a human immune system was comparable in both mouse strains. However, the expression of HLA transgenes resulted in more efficient clearance of an adenovirus infection from the liver, which correlated with liver-infiltration and activation of T cells and the detection of antigen-specific adaptive immune responses. While additional modifications to the xeno-recipient may further improve human immunity this study provides first evidence for functional antiviral immunity against a hepatotropic pathogen
PD-1, IL-10 and IFN-γ form a network to regulate HIV-specific CD4 T cell dysfunction (105.2)
Authors: Porichis Filippos , Kwon Douglas , Jennifer Zupkosky , Hart Meghan , McMullen Ashley , Freeman Gordon , Kavanagh Daniel , Kaufmann Daniel 
Published: January 2023

Abstract
Blockade of the PD-1 or IL-10 pathways can restore antigen-specific T cell functions in chronic infections and cancer. PD-1 blockade is currently evaluated in oncology trials and is also considered in HIV infection. It is thus crucial to define the immune restoration elicited by these interventions, and to determine whether combined blockade of these molecules can synergistically revive immune function. We investigated 40 subjects at different stages of HIV infection. We measured proliferation and cytokine production by HIV-specific CD4 T cells stimulated with HIV Gag in the presence of blocking antibodies against PD-L1 and/or IL-10Rα, or IFN-γ. We also determined the modulatory impact of IFN-γ on PD-1 and its ligands on different cell subsets. In viremic subjects, combined blockade of PD-L1 and IL-10Rα resulted in a striking synergistic increase in IFN-γ secretion by HIV-specific CD4 T cells in contrast to only a moderate increase in IL-2 and IL-13 secretion, and proliferation. While IL-10Rα blockade preferentially increased IFN-γ, PD-L1 blockade had a balanced effect on IFN-γ, IL-2 and IL-13. Stimulation of HIV-specific CD4 T cells led to strong up-regulation of PD-L1 on monocytes that was further increased by anti-IL-10Rα. Blockade of IFN-γ abrogated PD-L1 induction and restored proliferation of HIV-specific CD4 T cells. These data provide a mechanistic insight on how the interplay between PD-1, IL-10 and IFN-γ regulates Thelper dysfunction in HIV infection.
PD-1 blockage reverses immune dysfunction and hepatitis B viral persistence in a mouse animal model (105.23)
Authors: Tzeng HorngTay , Chen PeiJer , Hsu PingNing 
Published: January 2023

Abstract
Persistent hepatitis B viral (HBV) infection results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Recent studies in animal models of viral infection indicate that the interaction between the inhibitory receptor, programmed death (PD)-1, on lymphocytes and its ligand (PD-L1) play a critical role in T-cell exhaustion by inducing T-cell inactivation. We studied T-cell exhaustion and the effects of PD-1 and PD-L1 blockade on intrahepatic infiltrating T-cells in our recently developed mouse model of HBV persistence. In this mouse animal model, we demonstrated that there were increased intrahepatic PD-1-expressing CD8+ T-cells and increased CD4+ FoxP3+ T cells in mice with HBV persistence, but PD-1 upregulation was resolved in mice which had cleared HBV. The Intrahepatic CD8+ T-cells expressed higher levels of PD-1 and lower levels of CD127 in mice with HBV persistence. Blockade of PD-1/PD-L1 interactions increased HBcAg-specific interferon (IFN)-γ production in intrahepatic T lymphocytes. Furthermore, blocking the interaction of PD-1 with PD-L1 by an anti-PD-1 monoclonal antibody (mAb) reversed the exhausted phenotype in intrahepatic T lymphocytes and viral persistence to clearance of HBV in vivo. Our results indicated that PD-1 blockage reverses immune dysfunction and viral persistence of HBV infection in a mouse animal model, suggesting that the anti-PD-1 mAb might be a good therapeutic candidate for chronic HBV infection.
Kynureninase is the conserved self-antigen mimicked by the 2F5 Neutralizing Epitope of HIV-1 gp41 (105.35)
Authors: Yang Guang , Holl T. , Liu Yang , Li Yi , Lu Xiaozhi , Nicely Nathan , Kepler Thomas , Alam S. , Liao Hua-Xin , Cain Derek , Spicer Leonard , VandeBerg John , Haynes Barton , Kelsoe Garnett 
Published: January 2023

Abstract
Accumulating evidence suggests that the generation of neutralizing HIV-1 antibody may be proscribed by immunological tolerance. A significant majority of monoclonal human antibodies, including 2F5, that neutralize multiple clades of HIV-1 are polyreactive and bind avidly to unknown components of mammalian cells. Knock-in mice expressing the VH and VL regions of 2F5 are characterized by a central defect in B-cell development that indicates the presence of a tolerizing autoantigen(s) that is mimicked by the membrane-proximal, 2F5 epitope of HIV-1 gp41. If immunological tolerance does indeed prevent regular expression of 2F5-like neutralizing HIV-1 antibody, then discrete autoantigens that structurally mimic the HIV-1 2F5 epitope must be present in those mammalian species unable to make 2F5-like antibody. We now demonstrate that the 2F5 antibody and its unmutated ancestor avidly bind human kynureninase (KYNU), a conserved enzyme of tryptophan metabolism. The H4 domain of most mammalian KYNU contains the complete 2F5 epitope (ELDKWA) of gp41; a H4 mutation of human KYNU to that (ELEKWA) of laboratory opossums resulted in a fully active enzyme completely unreactive with the 2F5 antibody. Immunization of opossums with HIV-1 gp140 induced extraordinary titers of ELDKWA antibody but little or no response to adjacent gp41 epitopes. Identification of an epitope shared by most mammals and HIV-1 provides direct evidence that immunological tolerance can impair humoral responses to HIV-1.
Epitope specificity appears to be an important determinant of in vivo killing ability of simian immunodeficiency virus (SIV)-specific CD8+ T cells (105.43)
Authors: Pozzi Lu-Ann , Carville Angela , Varner Valerie , Sen Jayita , Knipe David 
Published: January 2023

Abstract
CD8+ cytotoxic T lymphocytes (CTL) are a critical component of antiviral immunity and play an important role in the control of lentiviruses. We have developed an in vivo CTL assay to directly measure the killing capacity of MHC-restricted SIV-specific CTL in rhesus macaques (RM) vaccinated with a recombinant herpes simplex virus prime/ DNA boost SIV vaccine regimen. Tetramer frequencies of Mamu-A*02-restricted Nef YY9-specific CD8+ T-cells were at least 10-fold higher than Mamu-A*02-restricted Gag GY9-specific CD8+ T-cells in individual animals both pre- and post-challenge. Prior to SIV challenge, both CTL populations showed poor and incomplete killing (22-35%) of target cells over 18 hours. Seven weeks post-challenge, there was a marked increase in the CTL killing capacity of both Nef YY9 and Gag GY9-specific CTL with 26-38% killing occurring over the first two hours and up to 100% killing over 18 hours. Surprisingly, Gag GY9-specific CTL consistently showed equivalent or greater in vivo killing when compared to Nef YY9-specific CTL even though the percentages of IFN-γ secreting and degranulating cells upon peptide stimulation were comparable. These data suggest that epitope specificity rather than tetramer frequency determines the ability of SIV-specific CTL to kill infected cells. Taken together, these data may have important implications for the development of a successful HIV vaccine.
Proteome wide mapping of Dengue Virus-specific T cell responses in human donors reveals antigenic hot spots and a dominance of HLA B restricted responses (105.52)
Authors: Weiskopf Daniela , Angelo Michael , Sidney John , Greenbaum Jason , Fernando Anira , Broadwater Anne , Kolla Ravi , De Silva Aruna , de Silva Aravinda , Grey Howard , Shresta Sujan , Peters Bjoern , Sette Alessandro 
Published: January 2023

Abstract
The frequency of dengue virus (DENV) infection has increased dramatically in the recent decades and the lack of a vaccine has led to significant worldwide morbidity and mortality. To improve on the minimal information available regarding HLA-restricted T cell responses resulting from natural infection with DENV, we endeavored to map T cell responses in individuals with resolved DENV infection. To cover a wide range of HLA phenotypes we first performed bioinformatics predictions of MHC binding motifs of all four DENV serotypes to 16 HLA A and 11 HLA B alleles. To validate this approach, we have tested the predicted motifs in an ex vivo ELISPOT assay for their ability to induce an IFNγ response in HLA-matched PBMC of 250 blood donors from Sri Lanka where DENV is hyper-epidemic. This proteome-wide screen has identified a total of 408 epitopes across all 10 DENV proteins (C, M, E, NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5). Interestingly, the majority of responses were derived from the highly conserved nonstructural proteins: NS3, NS4B and NS5. Additionally, we have observed a striking dominance of HLA B restricted responses in terms of breath as well as magnitude of the DENV specific response detected. Our data provides specific insight and understanding into the nature of HLA-restricted T cell responses, the role of T cells in DENV infection, and future strategies in vaccine design against this globally intensifying viral threat.
Vitamin A deficiency alters antibody forming cell and CD8+ T cell responses following intranasal vaccination with a respiratory virus vaccine (105.9)
Authors: Hurwitz Julia , Surman Sherri , Jones Bart , Sealy Robert , Woodland David , Rudraraju Rajeev 
Published: January 2023

Abstract
Vitamin A deficiency (VAD) has profound effects on immune responses in the gut, but its influence on other mucosal sites is less well understood. Sendai virus (SeV) is a candidate human parainfluenza virus type I (hPIV-1) vaccine, and a candidate vaccine vector for other respiratory viruses. A single I.N. dose of SeV elicits a protective immune response against hPIV-1 within days after vaccination. To define the effect of VAD on responses toward SeV, we monitored antibody forming cells (AFC) and immunodominant CD8+ T cells in mice. VAD inhibited SeV-specific IgA producing AFCs in the upper respiratory tract (URT) and biased the AFC response in favor of IgG-producing cells in the lower respiratory tract (LRT). In contrast, there was a dramatic reduction of CD8+ T cell frequencies in the LRT airways of VAD animals. Responding CD8+ T cells exhibited unusually high CD103 expression. In both VAD and control mice, e-cadherin (the ligand for αE(CD103)β7) was well expressed in URT tissues, but was expressed only weakly in the LRT. Results support a working hypothesis that the high CD103 expression among responding T cells in VAD mice may enhance T cell entrapment by e-cadherin and inhibit cell egress into the LRT airway. Our results highlight the concept that VAD does not exclusively affect immune responses in the gut, but has dramatic influences on immune cell function and residence in the respiratory tract.
Sensing of low-dose soluble antigen via Immunoglobulin E (106.1)
Authors: Platzer Barbara , Baker Kristi , Schopoff Sandy , Turley Shannon , Blumberg Richard , Fiebiger Edda 
Published: January 2023

Abstract
Dendritic cells (DCs) are the most potent antigen presenting cells and continuously encounter exogenous antigens at low dose. We show here that DCs use IgE-mediated antigen uptake to efficiently sense soluble antigen at a dose range that otherwise escapes immune detection. IgE-mediated antigen sampling via Fc-epsilon-RI simultaneously shuttles into the direct MHC class II-restricted presentation and the cross-presentation pathway resulting in the activation of Th2-type CD4+ T cells as well as cytotoxic CD8+ T cells (CTLs). Fc-epsilon-RI stabilizes at the cell surface of DCs after monovalent ligation with IgE. Antigen-mediated crosslinking of the receptor induces internalization into endo/lysosomal compartments. Absence of IL-12 production during IgE-mediated antigen uptake and presentation is critical for shifting the CD4 response towards Th2, but does not affect the generation of CTLs. Presence of IL-12 during IgE-mediated presentation redirects the immune response towards Th1 by suppressing the production of IL-4 and IL-13. Neither basophils nor mast cells can induce primary T cell responses after antigen sampling via IgE. These results establish a uniquely sensitive pathway for the detection of soluble exogenous antigen by DCs with high relevance for IgE-mediated immune responses in humans.
The function of HSP90 in MHC class II presentation (106.31)
Authors: Deffit Sarah , Blum Janice 
Published: January 2023

Abstract
A role for heat shock proteins (HSP) in promoting antigen presentation via the MHC class I pathway is well established and appears to play a key role in host recognition of tumors and transformed cells. Studies suggest that some HSP may promote the presentation of cytoplasmic antigens via the class I pathway, as well as selecting cytoplasmic antigens for presentation in the context of MHC class II molecules. A role for intracellular HSP90 as well as HSC70 in regulating the presentation of a cytoplasmic autoantigen, glutamic acid decarboxylase (GAD) has been demonstrated in B lymphoblasts. Modulating intracellular expression of HSP90 alpha in human B lymphoblasts altered class II presentation of GAD epitopes. Yet, diminished cellular HSP90 alpha expression did not alter the steady state levels of GAD antigen, or disrupt the trafficking of this native antigen from the cytoplasm to membraneous intracellular organelles. This may suggest HSP90 acts after antigen processing to promote epitope transit into endosomal/lysosomal compartments. Prolonged knockdown of HSP90 alpha in B cells, lead to an increase in the expression of HSP90 beta subunit. Studies are currently underway to examine whether the activation state of B cells influences cytoplasmic antigen presentation as well as the role of HSP90 co-factors in regulating this pathway for class II presentation.
Increased heterogeneity of MHC-II antigen presentation by B cells from older individuals (106.33)
Authors: Clark Heather , Banks Richard , Jones Leola , Burant Christopher , Canaday David 
Published: January 2023

Abstract
Why many current vaccines are less effective in older individuals is not fully understood. Immunosenescence of antigen presenting cells may contribute to this. We compared the function of peripheral blood B-cells from 10 young (age 22-45) and 11 old subjects (age 62-92) using a novel T-cell hybridoma system that specifically measures the B-cell receptor (BCR)-mediated MHC-II antigen presentation. We compared whole antigen (anti-BCR) that requires uptake and processing with peptide that can be directly presented on the cell surface. The mean magnitude of BCR-mediated antigen presentation was the same in older and younger subjects. Older subjects, however, showed increased heterogeneity of BCR-mediated antigen presentation. As a result, 5 of 11 geriatric subjects demonstrated inferior processing and presentation at all concentrations of anti-BCR antigen compared to the results from all younger subjects studied. The magnitude and variability of peptide that is presented but does not require processing was the same between groups. Surface BCR and HLA-DR expression showed no significant difference between groups. In contrast, both antigen processing and presentation function by blood monocytes had similar magnitude and variability between the older and younger subjects. These data suggest that poor B-cell antigen processing resulting in diminished presentation in some older individuals may contribute to poor vaccine responses.