bluuebunny/crossref_metadata_2025_split huggingface dataset:
The polyfunctionality of memory CD8+ T cells in response to chronic and acute viral infections is not influenced by age (105.49)
Authors: Lelic Alina , Ventresca Mario , Verschoor Chris , Parsons Robin , Evelegh Carol , Bowdish Dawn , Betts Michael , Loeb Mark , Bramson Jonathan 
Published: January 2023

Abstract
As humans age, they experience a progressive loss of thymic function and a corresponding shift in the nature of the circulating CD8+ T cell population from naïve to memory phenotype. These alterations are believed to result in impaired development of CD8+ T cell immunity in older individuals; however evidence that these global changes impair antigen-specific CD8+ T cell responses in the elderly is lacking. To address this possibility, we studied CD8+ T cell memory development following primary exposure to West Nile virus (WNV) in a cohort of young (&lt;40 yrs), middle-aged (41-60 yrs) and aged (&gt;61 yrs) individuals using polychromatic flow cytometry. Although the aged cohort displayed the previously described alterations in the CD8+ T cell compartment, including a marked loss of naïve CD8+ T cells, accumulation of CD28- and CD57+ T cells, we did not observe any influence of age on either the breadth, magnitude or functionality of antigen-specific CD8+ T cells following WNV, cytomegalovirus (CMV) or Epstein-Barr virus (EBV) peptide stimulation. We did however observe virus-specific CD8+ T cell functional differences between WNV, CMV and EBV. Collectively these data fail to support the hypothesis that immunosenescence leads to defective CD8+ T cell immunity and suggest that it should be possible to develop CD8+ T cell vaccines to protect aged individuals from infections with novel and emerging viruses.
Inverse relationship between T-cell receptor αβ repertoire diversity and pathogen-specific antibody levels in human cytomegalovirus infection (105.51)
Authors: Wang George , Dash Pradyot , McCullers Jonathan , Doherty Peter , Thomas Paul 
Published: January 2023

Abstract
A diverse T-cell receptor (TCR) repertoire capable of recognizing a broad range of antigenic peptides is thought to be central to effective pathogen-specific immunity, but evidence that TCR diversity is important for the successful control of human infections is limited. A novel, single-cell strategy for the clonotypic analysis of human CD8+ TCRαβ repertoires was used to probe the diversity and magnitude of individual human cytomegalovirus (CMV)-specific CD8+ T-cells recovered directly ex vivo. We found that CD8+ TCRαβ repertoire diversity, but not the size of the CD8+ T-cell response, was inversely related to circulating CMV-specific antibody levels, a measure that has been correlated epidemiologically with differential mortality risks and found here to be higher in persons with detectable (versus undetectable) CMV viral loads. Overall, these findings indicate that CD8+ T-cell diversity may be more important than T-cell abundance in limiting the negative consequences of CMV persistence, and provides insights into the selection of TCRαβ public motifs in a life-long virus infection.
IFN-γ secretion by memory CD4 T cells mediates immunopathology during secondary influenza infection by enhancing local lymphoid responses (105.6)
Authors: Bickham Kara , Turner Damian , Farber Donna 
Published: January 2023

Abstract
During secondary flu infection, flu-specific memory CD4 T cells induce protection and exacerbate cellular infiltration and inflammation. We investigated the role of IFN-γ production by memory CD4 T cells in the development of lung immunopathology during secondary flu infection by generating and analyzing in vivo responses of memory IFN-γ deficient CD4 T cells. We found similar precursor frequencies of flu-specific CD4 T cells after primary influenza infection of IFN-γ-/- and WT mice, with IFN-γ-/- memory CD4 T cells producing rapid IL-2 and TNF-α compared to the predominant IFN-γ and IL-2 production by WT memory CD4 T cells. Adoptive transfer of equal numbers of flu-specific WT and IFN-γ-/- memory CD4 T cells into naïve mouse hosts resulted in increased pulmonary infiltration and hypoxia 7 days after flu challenge only in recipients of WT memory CD4 T cells. Notably, flu-specific WT cells in the MLN exhibited increased expansion and activation compared to flu-specific IFN-γ-/- CD4 T cells. Furthermore, lung homogenates from recipients of WT memory CD4 T cells had significantly higher levels of the chemokines, CCL4 and CCL5, compared to recipients of IFN-γ-/- CD4 T cells. These findings suggest that IFN-γ secretion by memory CD4 T cells acts as a potential switch for the development of immunopathology, possibly by recruiting DCs to the lung, which in turn migrate to the MLN for activation and priming of large numbers of CD4 and CD8 cells
Neutralizing anti-HIV antibodies develop in a humanized mouse model of HIV-1 infection (105.8)
Authors: Seung Edward , Dudek Timothy , Dugast Anne-Sophie , Mattoo Hamid , Vrbanac Vladimir , Tivey Trevor , Cariappa Annaiah , Pillai Shiv , Luster Andrew , Tager Andrew 
Published: January 2023

Abstract
In BLT (bone marrow-liver-thymus) humanized mice, human thymocytes are educated by autologous human thymic tissue, resulting in functional human T cells. In contrast, limitations to B cell maturation have been noted. But despite this, we show for the first time that HIV infected BLT mice can produce class-switched anti-HIV antibodies with neutralizing activities. Human transitional B cells were present in greater frequencies in BLT mice than adult humans. Most of these cells had a T1 phenotype in the blood and spleen. But despite this B cell maturation defect, class-switched IgG Abs against various HIV proteins were detected by Western Blot in HIV-infected BLT mice. Using ELISA to determine anti-p24 IgG Ab titers, Abs were present as early as 8 weeks post infection (p.i.), with peak Ab titers seen after 15 weeks. One infected mouse demonstrated a peak titer similar to that seen in a chronically infected human. Finally, plasma samples from infected BLT mice after 22 weeks p.i. demonstrated neutralizing activities against the challenge virus. IC50 neutralizing titers in these mice were greater than those from humans infected for up to 5 months, but less than one infected for several years. The ability of humanized BLT mice to generate functional humoral immune responses may be further improved by strategies to improve their B cell maturation, which will further improve the potential of these mice to become a model system to study candidate HIV vaccines and therapies.
In vivo analysis of antigen presentation during acute CNS viral infection (106.11)
Authors: Fan Ying , Nayak Debasis , McGavern Dorian 
Published: January 2023

Abstract
Antigen presenting cells (APCs) upon activation break down proteins into peptides that are presented on major histocompatibility complexes (MHC). APCs help shape immune responses at sites of viral infection and can foster the development of immunopathology. Intracerebral infection of mice with lymphocytic choriomeningitis virus (LCMV) induces a CD8 T cell-dependent fatal meningitis. Because little is known about the dynamics of antigen-presentation in the brain, we set out to identify the APCs that influence CD8 T cell motility and function during the development of meningitis. This was accomplished by generating a LCMV recombinant expressing ovalbumin (OVA), which enabled us to quantify in vivo presentation of OVA257-264 (SIINFEKL) peptides by H-2Kb. We also used two-photon (2P) microscopy to study interactions between virus-specific CD8 T cells and different APC populations in the virally infected brain. Surprisingly, our results revealed that all brain resident APCs (dendritic cells, macrophages, and microglia) contained LCMV antigen during the development of meningitis, but only microglia had detectable H-2Kb-OVA257-264 complexes on their cell surface. The presentation capacity of microglia was confirmed by 2P data showing extensive CD8 T cell interactions and clustering around microglia. During LCMV meningitis, our findings suggest that CD8 T cell interactions with brain resident microglia are favored over those with peripherally-derived professional APCs.
Cutaneous delivery of Poly(dG) conjugated protein antigens targets and activates dendritic cells in vivo. (106.13)
Authors: Toussaint Hélène , Erdos Geza , Larregina Adriana , Donahue Cara , Falo Louis 
Published: January 2023

Abstract
Efficient and specific targeting of antigen (Ag) to Ag presenting cells (APCs) in vivo is a critical challenge for vaccine design. Ag delivery and formulation strategies have been directly linked to type and the quality of induced immune responses. APCs acquire Ags in a variety of forms from a variety of sources and endocytic mechanisms can predetermine intracellular Ag routing, processing and presentation to CD4 or CD8 T cells. We have designed an APCs targeting strategy based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein Ags. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (Poly(dG)-OVA) are rapidly internalized by DCs and follow distinct intracellular processing pathways. Importantly, immunization of naïve animals by direct injection of Poly(dG)-OVA induces protective multifunctional T cell immunity. This includes efficient priming of potent antigen specific CTL responses, differentiation of naïve CD4 T cells into Th1 CD4 T cells, induction of specific memory T cell responses, and generation of Ag-specific antibody responses. Extending our findings to human skin, we show that intradermal injection of Poly(dG)-Ag results in efficient uptake by human skin migratory DCs, preferentially dermal CD14+ DCs, that also acquire potent T cells stimulatory functions. Our data suggest that Poly(dG) can both target Ags to human skin immune APCs and function as an adjuvant to induce potent CD4 and CD8 mediated T cell immunity.
CD13 regulates dendritic cell cross-presentation and t cell responses by inhibiting receptor-mediated antigen uptake (106.16)
Authors: Ghosh Mallika , McAuliffe Beata , Subramani Jaganathan , Basu Sreyashi , Shapiro Linda H 
Published: January 2023

Abstract
Dendritic cell (DC) antigen cross-presentation is generally associated with immune responses to tumors and viral antigens and enhancing this process is a focus of tumor vaccine design. In this study, we found that the myeloid cell surface peptidase CD13 is highly and specifically expressed on the subset of DCs responsible for cross-presentation, the CD8+ murine splenic DCs. In vivo studies indicated that lack of CD13 significantly enhanced T cell responses to soluble OVA antigen, although the development, maturation, antigen processing and presentation of DCs is normal in CD13KO mice. In vitro studies showed that CD13 regulates receptor-mediated, dynamin-dependent endocytosis of antigens such as OVA and transferrin but not fluid-phase or phagocytic antigen uptake. CD13 and antigen are co-internalized in DCs but CD13 did not co- immunoprecipitate with antigen receptors, suggesting that CD13 does not control internalization of specific receptors but regulates endocytosis at a more universal level. Mechanistically, we found that phosphorylation of the endocytic regulators p38MAPK and Akt was dysregulated in CD13KO DCs and blocking these kinases perturbed CD13-dependent endocytic uptake. Therefore, CD13 is a novel endocytic regulator that may be exploited to enhance antigen uptake and T cell activation to improve the efficacy of tumor-targeted vaccines.
Role for Rab11a in mediating TLR dependent cross-presentation responses (106.17)
Authors: Nair Priyanka , Florey Oliver , Baccarini Alessia , Overholtzer Michael , Brown Brian , Blander J. 
Published: January 2023

Abstract
Toll-like receptor (TLR) signaling is critical for accelerated phagosome maturation and enhanced major histocompatibility complex class II (MHC II) presentation of phagocytosed antigens. Since cross-presentation is another consequence of phagosome maturation, we hypothesized that like MHC II presentation, the presentation of exogenous antigens on MHC class I (MHC I) by dendritic cells (DCs) is positively regulated by TLRs. Using antigen derived from bacteria, infected apoptotic cells or antigen-coated beads conjugated to a TLR ligand, our results show that cross-presentation is severely impaired when TLR signaling is abrogated in the cross-presenting DC or when TLR ligands are absent from phagocytic cargo. To delineate the mechanisms behind TLR enhancement of cross-presentation, we studied trafficking of MHC I in the presence or absence of TLR signaling. We observed recruitment of MHC I selectively to phagosomes containing TLR ligands along with the concomitant enrichment of the small guanosine tri-phosphatase (GTPase) Rab11a. In fact, Rab11a was crucial for TLR mediated enhancement of cross-presentation as selective knock-down of Rab11a abrogated the ability of DCs to cross-present antigen. Our results demonstrate a role for Rab11a in trafficking MHC I to phagosomes that engage TLR signaling, thus mediating enhanced cross-presentation of microbial antigens. Results from our studies have implications on anti-viral and anti-bacterial immunity as well as tumor immunotherapy.
The immunoproteasome is expressed by lymphocytes and plays critical roles in lymphocyte development (106.34)
Authors: Zanker Damien , Pang Ken , Chen Weisan 
Published: January 2023

Abstract
The immunoproteasome (IP) differs from the housekeeping proteasome through the substitution of the catalytically active β1, β2 and β5 subunits for LMP2, MECL-1 and LMP7, respectively. The major function of the immunoproteasome is proposed to enhance immune responses by providing peptides optimal for class I binding. Interestingly, LMP2-/- mice have significantly reduced thymocytes and peripheral lymphocytes, a phenotype not easily explained by its proposed role. To explore this, we compared thymocytes and splenocytes from wild type and LMP2-/- mice. In the periphery, LMP2-/- mice have decreased lymphocytes but normal numbers of other BM derived cell types. In the thymus, staging analysis indicated a developmental halt with increased apoptosis, at the CD4-CD8- stage at the transition from DN3 to DN4. Similarly, a halt was found in the B cell lineage at the immature to T1 B cell transition. We confirmed by WB that developing wild type T and B cells express IP subunits. The NFκB pathway plays an important role in lymphocyte survival at these stages. Various NFκB proteins were investigated by WB and confocal microscopy following pathway activation. Subsequently, we detected decreased degradation of IKBα, p105 and p100 from LMP2-/- mice. Together, these results provide a link between the IP and the NFκB pathway at crucial lymphocyte developmental stages. We have therefore demonstrated the IP also plays important housekeeping roles other than simply enhancing antigen processing.
Stimulation of the immune system by small chemicals can be independent of hapten-protein conjugate formation and is regulated by the TCR avidity for the HLA-drug complex (106.51)
Authors: Adam Jacqueline , Eriksson Klara , Schnyder Benno , Fontana Stefano , Pichler Werner , Yerly Daniel 
Published: January 2023

Abstract
Rationale: The antiretroviral drug abacavir (abc) elicits a strong CD8-mediated immune response in HLA-B*5701+ subjects. We used this model to study the interaction of small chemicals with the immune system. Methods: We generated abc-specific T-cell clones (abc-TCC) from HLA-B*5701+ donors and analyzed their specific activation in Ca2+ influx assays and by annexin V staining. Results: Abc-metabolizing enzymes were absent in immune cells and inhibition of the proteasome in antigen presenting cells did not affect TCC reactivity. Five out of 50 abc-TCC reacted instantly (~120 sec) to soluble abc presented on HLA-B*5701, whereas many other TCC reacted after 20 min or later. Increasing the number of HLA-B*5701/abc immunogenic complexes by increasing the abc concentrations and/or using transfected cells with a high HLA-B*5701 expression accelerated the abc-TCC activation kinetic. Analysis of several abc-TCC revealed different TCR Vβ-segments, demonstrating their polyclonality. Conclusions: Since the observed abc-reactivity was metabolism- and processing- independent, an immune activation by small chemicals can occur without covalent drug binding to a carrier protein. Moreover, titration experiments revealed different TCC reactivity patterns. This finding suggests a crucial role of the TCR avidity for the drug in regulating T cell activation. These data have implications in drug regulation of the immune system as well as for understanding drug hypersensitivity.
MDA5 cooperatively forms dimers and ATP-sensitive filaments upon binding double-stranded RNA (108.1)
Authors: Modis Yorgo , Berke Ian 
Published: January 2023

Abstract
MDA5 detects viral double-stranded RNA in the cytoplasm. RNA binding induces MDA5 to activate the signaling adaptor MAVS through interactions between the caspase recruitment domains (CARDs) of the two proteins. The molecular mechanism of MDA5 signaling is not well understood. Here we show that MDA5 cooperatively binds short RNA ligands as a dimer with a 16-18-bp footprint. A crystal structure of the MDA5 helicase-insert domain demonstrates an evolutionary relationship with the archaeal Hef helicases. In X-ray solution structures, the CARDs in unliganded MDA5 are flexible, and RNA binds on one side of an asymmetric MDA5 dimer, bridging the two subunits. On longer RNA, full-length and CARD-deleted MDA5 constructs assemble into ATP-sensitive filaments. We propose a signaling model in which the CARDs on MDA5-RNA filaments nucleate the assembly of MAVS filaments with the same polymeric geometry. Ian C. Berke & Yorgo Modis (2012) MDA5 cooperatively forms dimers and ATP-sensitive filaments upon binding double-stranded RNA. EMBO J., in press.
Type I Interferons induce TREX1 in myeloid dendritic cells. (108.10)
Authors: Xu Jun , Gamero Ana , Gallucci Stefania 
Published: January 2023

Abstract
Dendritic cells (DCs) are activated by endogenous and exogenous danger signals to stimulate T and B cell responses. Type I Interferons (IFNα/β) are endogenous danger signals able to activate DCs and induce the expression of IFN-stimulated genes (ISGs) that include genes important in host defense against viruses. Although some ISGs have been demonstrated to have antiviral functions, the antiviral activities of the majority of ISGs have not been confirmed. TREX1 (Three prime Repair EXonuclease1) is an exonuclease acting on ssDNA or mispaired 3’ termini. It has been associated with autoimmune diseases including Systemic Lupus Erythematosus and Aicardi-Goutieres Syndrome, which show over-expression of ISGs. TREX1 also facilitates HIV-1 infection by degrading cytosolic HIV-1 DNA, suggesting that HIV-1 may use TREX1 to escape host detection. The role of TREX1 in DC function is unknown. We have found that IFNα stimulates TREX1 expression in C57BL/6 bone marrow derived Dendritic Cells (myeloid DCs). TREX1 gene expression is induced within 1 h of IFNα treatment and continues to increase up to 6 h after stimulation, indicating that TREX1 is an early responsive ISG with sustained expression possibly due to autocrine IFNβ production. In addition, transcription of TREX1 by IFNα is impaired in myeloid DCs from Stat2-deficient mice, indicating that TREX1 expression is dependent on the canonical IFNAR/STAT2 signaling pathway. We are now studying TREX1 role in the antiviral response of DCs.
molecular mechanisms of innate signaling disruption by human metapneumovirus M2-2 protein (108.15)
Authors: Bao Xiaoyong , Ren Junping , Wang Qingrong , Kolli Deepthi , Prusak Deborah , Wood Thomas 
Published: January 2023

Abstract
hMPV is a leading cause of respiratory infections in pediatric populations globally. Neither an effective cure for hMPV nor a vaccine to prevent hMPV infection is available. Recently, a recombinant hMPV lacking the M2-2 protein (ΔM2-2) demonstrated reduced replication in the respiratory tract of animal models, making ΔM2-2 a promising live vaccine candidate. However, the exact nature of the interaction between the M2-2 protein of hMPV and host cells that regulates viral infection and propagation is largely unknown. In this study, we found that, in addition to its role as a critical regulator of viral RNA synthesis, M2-2 is also an important virulence factor that antagonizes RIG-I/MAVS-mediated cellular signaling, revealing a novel function of M2-2. In reporter gene assays, the M2-2 protein specifically inhibited RIG-I- and MAVS-dependent IFN-β gene transcription, but not the one induced by downstream effectors of MAVS, suggesting that M2-2 targets MAVS in a viral-RNA-independent manner. Coimmunoprecipitation assays revealed that the M2-2 protein interacts with MAVS. In agreement with these findings, ΔM2-2-infected airway epithelial cells produced higher levels of type I interferon and other pro-inflammatory mediators than WT-infected cells. Activation of transcription factors IRF-3 and NF-κB, and induction of their dependent gene transcription were also enhanced by ΔM2-2 infection, confirming the inhibition of hMPV-induced innate signaling by M2-2.
The effects of indoleamine 2,3 dioxygenase on the immune response to Influenza A infection. (108.4)
Authors: Rose David , Tompkins S. , Mellor Andrew , Klonowski Kimberly 
Published: January 2023

Abstract
Indoleamine 2,3 dioxygenase (IDO) is the enzyme responsible for the first step of tryptophan metabolism in the Kynurenine pathway and is a known immunosuppressant. IDO can suppress the T cell response to various antigens via tryptophan starvation, production of toxic byproducts of the kynurenine pathway, or a combination of both. Conversely, 1-methyl-tryptophan, a tryptophan analog that cannot be metabolized by IDO, has been shown to enhance immune responses in both pregnancy and tumor models. While IDO has primarily been studied in the context of adaptive immune responses, little is known about its effect on NK cells. While IDO is expressed at a basal levels by dendritic cells in many tissues, IDO levels are enhanced in the lungs early after influenza A infection where NK cells are not only positioned as the first line of anti-viral defense but also act to bridge the innate and adaptive immune response. Using IDO-1 deficient mice we will report the qualitative and quantitative differences of the NK cell response to influenza A infection in an IDO deficient environment.
B cell development and immunoglobulin production are altered in the absence of IκBNS (109.4)
Authors: Touma Maki , Saito Ibuki , Reinherz Ellis , Clayton Linda 
Published: January 2023

Abstract
NF-κB transcription factors are key mediators of immune function as well as inflammatory responses. The activation of NF-κB is regulated by several IκB proteins, a family comprising classical cytoplasmic as well as nuclear IκBs. In this study, we focused on the role of IκBNS, a nuclear IκB protein, in B lymphocyte development and function. Analysis of lymphoid tissues from IκBNS knockout (KO) mice revealed that a lack of IκBNS affects the development of peritoneal B-1 cells and splenic marginal zone B cells. Development of B-2 cells was essentially normal. We also found that B cell proliferative activity and immunoglobulin production were altered in the absence of IκBNS. These defects were confirmed by the analysis of B cells in bone marrow chimeric mice constructed by the transfer of wild type or IκBNS KO bone marrow cells into B cell-deficient mice. Furthermore, histological analysis of spleens from chimeric mice revealed that re-constitution of B cell areas, marginal zones and germinal centers were markedly reduced in IκBNS KO cell recipient mice. Examination of the functions of IκBNS KO B cell subsets suggested that IκBNS is important for antibody production by both marginal zone and follicular B cells. These results indicate that IκBNS plays a key role in peripheral B cell development and function.