bluuebunny/crossref_metadata_2025_split huggingface dataset:
The complex relationship between TRAF3 and B cell function (42.2)
Authors: Lin Wai , Hildebrand Joanne , Bishop Gail 
Published: January 2023

Abstract
TRAF3 is a negative regulator in B lymphocytes of CD40 and BAFF-R mediated signaling events, as well as basal B cell survival and homeostasis. Loss of function mutants of TRAF3 are associated with multiple myeloma (MM) and B-cell lymphoma, and TRAF3-/- B cells in mice show greatly enhanced survival, as well as constitutive activation of the alternative NF-κB2 pathway. Current dogma is that TRAF3 promotes degradation of the kinase NIK to control activation of the NF-κB2 pathway, and stimulation through CD40 or BAFF-R induces TRAF3 degradation, allowing NIK to activate NF-κB2, which promotes survival. However, our recent findings indicate a more complex regulatory mechanism. The A/WySnJ mouse expresses a mutant BAFF-R in which the C terminal 8 amino acids are replaced by a proviral sequence. BAFF ligation of this mutant receptor does not activate NF-κB2, but induces TRAF3 degradation comparable to Wt BAFF-R. Additionally, we analyzed a human MM-derived TRAF3 mutant and found that its expression enhanced NF-κB2 activation in B cells, but it is not degraded. Finally, we found that T cells or dendritic cells lacking TRAF3 also have constitutive NF-κB activation, but show no enhanced survival. Taken together, these data suggest that TRAF3 degradation or loss is not always necessary or sufficient to promote the NF-κB2 pathway, that activation of this pathway is insufficient to promote cell survival, and that TRAF3 plays cell-type-specific unique roles in B cell biology.
Prohibitins and the cytoplasmic domain of CD86 cooperate to mediate CD86 signaling in B lymphocytes (42.5)
Authors: Lucas Christopher , Cordero-Nieves Hector , Campbell Kerry , Bhatia Sumeena , Hodes Richard , Sanders Virginia 
Published: January 2023

Abstract
CD86 engagement on a CD40L/IL-4-primed murine B cell activates signaling intermediates that increase Oct-2 and IgG1 mRNA and protein expression, independent of class switch recombination. One of the most proximal intermediates identified is PLCγ2. Since the cytoplasmic domain of CD86 lacks tyrosine residues reported to bind PLCγ2, we used a proteomics-based identification approach to show that the tyrosine-containing transmembrane adaptor proteins, prohibitin-1 (Phb1) and prohibitin-2 (Phb2), bind to CD86. Although basal expression of Phb1/2 and association with CD86 was low in resting B cells, expression and association increased after CD40 engagement. The CD86-induced increase in Oct-2 and IgG1 was less when either Phb1/2 expression was reduced by shRNA or the cytoplasmic domain of CD86 was truncated or mutated at serine/threonine PKC-phosphorylation sites, but did not affect Phb1/2 binding to CD86. Furthermore, Phb1/2 reduction and CD86 truncation revealed that the CD86-induced phosphorylation of PLCγ2 required Phb1/2 alone; whereas, IκBα and NF-κB (p65) phosphorylation required both Phb1/2 and the CD86 cytoplasmic domain. Together, these findings suggest that Phb1/2 and the CD86 cytoplasmic domain cooperate to mediate CD86 signaling in a B cell to regulate IgG1 production and is the first evidence to define the molecular basis of membrane-proximal CD86 signal transduction in B cells.
The transcription factor T-bet regulates parasitemia and promotes pathogenesis during Plasmodium berghei ANKA murine malaria (43.16)
Authors: Oakley Miranda , Solanki Nehal , Lotspeich Cole Leda , Majam Victoria , Sahu Bikash , Derrick Steven , Morris Sheldon , Kumar Sanjai 
Published: January 2023

Abstract
CD4+ T cells are required for the pathogenesis of experimental cerebral malaria (ECM) during the induction phase of disease in mice. Using the Plasmodium berghei ANKA murine model of ECM and mice deficient for the transcription factor T-bet (the master regulator of Th1 cells) on the C57BL/6 background, we demonstrate that while Th1 CD4+ T cells play a role in the regulation of parasite burden, they also promote the pathogenesis of ECM possibly by invoking a robust proinflammatory response. We find that while 100% (10/10) of wildtype mice developed ECM by day 9 post-infection, only 30% (3/10) of T-bet deficient mice succumbed to disease during the cerebral phase of infection (p=0.000058). In addition, T-bet deficient mice had higher parasitemia than wildtype controls during the ECM phase of disease (17.7 +/- 3.1% verses 10.9 +/- 1.5%). These results indicate that T-bet dependent regulation of parasite burden may promote pathogenesis in this murine model of ECM. We are also investigating the effect of T-bet on protective immunity in the P. yoelii NL murine model and the P. chabaudi AS model during the acute and clearance phases and in recrudescence. In depth analysis of immune cells and cytokines is currently being performed to better understand how Th1 CD4+ T cells mediate their protective as well as pathogenic functions during malaria infection.
T-cells contribute to the pathogenesis of Staphylococcus aureus pneumonia (43.19)
Authors: Parker Dane , Prince Alice 
Published: January 2023

Abstract
Staphylococcus aureus is a leading cause of pneumonia and increasing evidence indicates the host response contributes to disease. We investigated the role of T-cells in S. aureus pneumonia. We initially utilized Rag2 null mice and infected them with S. aureus MRSA strain USA300 (the strain currently epidemic in the USA) for 20h. Rag2-/- mice showed reduced pulmonary pathology and improved bacterial clearance in bronchoalveolar lavage fluid (BALF) and lung tissue (85% reduction, P&lt;0.05) compared to wild-type mice. Examination of immune cells in the BALF and lung showed no differences between infected WT and Rag2 null mice. Levels of TNF, KC, IL-6 and IL-17 were significantly reduced (50%, 85%, 52%, 100% respectively, P&lt;0.01). We then focused on the role of CD4 cells. CD4 null mice infected with USA300 also exhibited reduced pulmonary pathology compared to wild-type mice as well as significantly fewer bacterial numbers in the BALF and lung parynchyma (reduced by 80% (P&lt;0.05) and 75% (P&lt;0.05) respectively). Although Cd4-/- mice also had no changes in lung cell populations they did have significantly reduced levels of TNF (68%, P&lt;0.01), KC (86%, P&lt;0.01), IL-6 (61%, P&lt;0.05) and IL-17 (48%, P&lt;0.05). Our data from these mouse models suggest that T-cells in response to S. aureus contribute significantly to inflammation and interfere with bacterial clearance in the lung. The modulation of T-cells may have a role in modifying the immune response to S. aureus and improving outcomes.
IgM memory B cells generated during bacterial infection are required for secondary IgG responses to antigenic challenge (43.2)
Authors: Yates Jennifer , Racine Rachael , McBride Kevin , Jones Maura , Winslow Gary 
Published: January 2023

Abstract
Immunological memory was long considered to be harbored in B cells that express high affinity class-switched IgG. More recently, IgM memory B cells have been identified following immunization with nominal antigens and adjuvants. Based on the expression of CD11c, we have identified a large population of such cells using a natural model of infection by the bacterium Ehrlichia muris. These CD11c+ IgM memory cells exhibit phenotypic characteristics of memory B cells, including expression of CD73, CD11b, and PD-L2. In addition, these CD11c+ IgM memory cells lack expression of CD138, are largely quiescent, and have accumulated somatic mutations. Although these cells did not proliferate or secrete antibody ex vivo, they produced antigen-specific IgM upon in vitro stimulation with mitogens. Furthermore, in vivo depletion abrogated the IgG recall response to specific antigenic challenge. Our findings are consistent with previous data demonstrating that IgM memory cells undergo class switch recombination and affinity maturation following re-encounter with cognate antigen. We propose that these CD11c+ IgM memory B cells are responsible for the IgG produced following secondary challenge in ehrlichial infection, and likely function to provide greater flexibility to variant antigenic challenges.
The Role of B Cells in the Immune Response to Mycobacterium tuberculosis. (43.3)
Authors: Kozakiewicz Lee , Maglione Paul , Xu Jiayong , Casadevall Arturo , Chan John 
Published: January 2023

Abstract
The role of humoral immunity in the immune response to Mycobacterium tuberculosis (Mtb) is poorly defined. B cells form aggregates with features of germinal centers and are prominent components of the lung granuloma in Mtb-infected humans, mice and macaques. Using muMT B cell-deficient mice, we showed that B cells were required for optimal granulomatous response and protection upon aerosol infection. muMT mice were more susceptible to Mtb with increased mortality and elevated lung bacterial burden. B cell-deficiency also resulted in exacerbated immunopathology with increased neutrophil influx and IL-10 production independent of tissue bacterial load. Transfer of B cells reversed the phenotypes of the muMT mice. This occurred in the presence of immunoglobulins (Igs) in the serum but without the presence of lung B cells. We showed that engagement of distinct Fcγ receptors (FcγR) divergently affected susceptibility to Mtb. Mice lacking activating FcγR showed increased mortality and bacterial load with enhanced lung neutrophil influx and IL-10 expression compared to wildtype, whereas mice lacking inhibitory FcγRIIB exhibited an augmented lung Th1 response. Thus, B cells via their ability to produce Igs may regulate T cell responses by immune complex engagement of FcγR on antigen presenting cells. The mechanisms by which B cells modulate the immune response to Mtb are being characterized by testing the immune response of transgenic mice deficient in B cells or Igs to infection.
Recombinant proteins encoded by genes present in Mycobacterium tuberculosis-specific regions of difference induce delayed-type hypersensitivity skin responses (43.31)
Authors: Mustafa Abu 
Published: January 2023

Abstract
The world-wide control of tuberculosis (TB) requires affordable and easy to apply test(s), which could differentiate TB from BCG vaccination and exposure to environmental mycobacteria. In this study, the proteins encoded by Mycobacterium tuberculosis-specific regions of difference (RD) genes, which are absent in BCG and most environmental mycobacteria, were studied for delayed-type hypersensitivity (DTH) skin responses in guinea pigs. The genes of RD1 (CFP10 and ESAT-6), RD7 (Rv2346 and Rv2347) and RD9 (Rv3619 and Rv3620) proteins were cloned in plasmid vectors and expressed in Escherichia coli. The expressed recombinant proteins were purified to homogeneity using affinity columns. Guinea pigs were injected with 1x1010 heat-killed M. tuberculosis, and phosphate buffered saline (PBS), as a placebo control. After four weeks of injection, all the animals were tested for DTH skin responses by intradermal injection with PBS (negative control), purified protein derivative (PPD) and sonicates of M. tuberculosis (positive control), and purified recombinant proteins. The results showed that PBS failed to induced DTH responses in any group, whereas PPD, M. tuberculosis sonicates and the recombinant proteins induced positive DTH responses in animals injected with heat-killed M. tuberculosis, but not in PBS-injected animals. These results suggest that purified RD proteins are active in inducing DTH responses in vivo, and may be useful in specific diagnosis of TB.
Acute alcohol exposure induces tolerance to endotoxin and reduces pro-inflammatory cytokine production: role for hsp70 and hsp90 (44.21)
Authors: Ambade Aditya , Deshpande Janhavee , Catalano Donna , Mandrekar Pranoti 
Published: January 2023

Abstract
Alcohol, a commonly abused drug in US, is linked to impaired host defense, increased susceptibility to infections. Acute alcohol exposure in humans and experimental animals attenuates endotoxin/LPS induced pro-inflammatory cell activation. Molecular mechanisms involved in these processes are unclear. Earlier, we showed that acute alcohol induces hsp70, reported to exert anti-inflammatory effects by inhibiting NFκB activity. Here we hypothesize that acute alcohol induces tolerance to a subsequent LPS challenge by regulation of hsp70 and hsp90. To test our hypothesis, RAW 264.7 mouse macrophages were exposed overnight to alcohol (25mM, 50mM) followed by LPS (100ng/ml) challenge. Pro-inflammatory cytokine, NFκB activity and heat shock transcription factor (HSF) 1, hsp70 and hsp90 expression was analyzed. Results show that overnight acute alcohol exposure decreased inflammatory cytokine, TNFα, production to a subsequent LPS challenge. Concomitantly acute alcohol induced HSF1 binding activity and hsp70 but reduced hsp90 levels in RAW macrophages. Hsp70 immunoprecipitation revealed that acute alcohol induces hsp70-NFκB-p50 complexes likely preventing NFκB DNA binding. Treatment of macrophages with hsp70 inhibitor, quercetin, partially blocked acute alcohol mediated down regulation of LPS-induced pro-inflammatory cytokine TNFα. Summarizing, our results indicate that acute alcohol induces endotoxin tolerance and reduced pro-inflammatory cytokines via HSF1 and hsp70 induction.
Adaptive immunity mediated by Natural Killer cells. (45.20)
Authors: Paust Silke , Flynn Michael , Wang Baozhong , Dougan Stephanie , Ploegh Hidde , Telenti Amalio , Compans Richard , von Andrian Ulrich 
Published: January 2023

Abstract
Adaptive immunity is thought to be a unique feature of T and B lymphocytes. However, there is mounting evidence that adaptive immunity can be mediated by a discrete subset of liver-resident natural killer (NK) cells. To date, Rag-independent NK memory has been documented for four distinct haptens and six viral antigens (Ag). We have developed a sorting strategy to identify and isolate Ag-specific NK cells from livers of Rag-/- mice sensitized with the hapten DNFB. By transplanting nuclei from sorted Rag-/- NK cells into enucleated oocytes, embryonic stem (ES) cell lines were generated that were used to clone mice. NK cells from the cloned animals instantly responded to DNFB without requiring prior sensitization, but they could not be sensitized to other Ags. Thus, the nuclear 'information' for Ag specificity of memory NK cells persists even in animals generated from a donor nucleus whose epigenetic state was reset by nuclear reprogramming. This apparent genetic fixation would be expected if Ag receptor specificity were encoded at the level of genomic DNA, rather than by epigenetic regulation of conventional 'hardwired' NK receptors, and suggest an entirely novel mechanism to generate Ag receptor diversity. Thus, current views of the immune system as a duality of adaptive (T and B cells) and innate (everything else) arms, need to be re-imagined as a trinity that includes memory NK cells as a third branch.
Obligate role of CXCR3 chemokine receptor for trafficking of effector CD8 T cells in the tumor microenvironment (46.14)
Authors: Mikucki Maryann , Skitzki Joseph , Fisher Daniel , Luster Andrew , Evans Sharon 
Published: January 2023

Abstract
Trafficking of tumor-reactive T cells across vascular checkpoints is a critical juncture in the effector phase of cancer immunity although this step is largely unexplored. We recently showed that poor trafficking of blood-borne CD8 effector T cells across tumor microvascular checkpoints is a significant obstacle to antitumor immunity. This bottleneck can be overcome by preconditioning regimens using systemic thermal therapy (STT, 39.5 ± 0.5°C, 6 h) that promotes E/P-selectin and ICAM-1-dependent trafficking of adoptively transferred CD8 T cells and subsequent lysis of tumor targets. Here we investigated the chemokine receptor requirements for trafficking of tumor-specific OT-I CD8 T cells across microvascular barriers in B16-OVA murine melanoma. We identified a non-redundant role for CXCR3, but not CXCR4, in T cell trafficking to tumors under both homeostatic and STT conditions using CXCR3-deficient OT-I T cells. Parallel results were observed by intravital microscopy whereby CXCR3 was necessary for T cells to undergo chemokine-dependent transition from rolling to firm arrest in tumor vessels of STT-pretreated mice. Taken together, these studies provide the first evidence that CXCR3 is obligatory for T cell trafficking across tumor vascular gateways and support strategic use of therapies to augment chemokine-dependent delivery of immune cells for the treatment of cancer. Supported by the NIH (CA79765, CA085183), and the Jennifer Linscott Tietgen Family Foundation.
A high frequency of naïve PR1-specific CD8+ T cells in umbilical cord blood and fetal thymus suggest incomplete central tolerance to the hematopoietic self-antigen PR1. (46.24)
Authors: St. John Lisa , Clise-Dwyer Karen , Patenia Rebecca , Sergeeva Anna , He Hong , Bollard Catherine , Shpall Elizabeth , Lu Sijie , Ma Qing , Molldrem Jeffrey 
Published: January 2023

Abstract
Tolerance to self-antigens is established primarily in the thymus by negative selection. We have evidence that central tolerance to the HLA-A2 restricted self-peptide, PR1, is incomplete. The frequency of PR1-CTL in umbilical cord blood (UCB) is significantly higher than that seen in the peripheral blood of healthy adults. Investigation in fetal thymic tissue (FT) showed that PR1 is expressed on the surface of thymic dendritic cells (DC) but not thymic epithelial cells. The level of PR1 expression on FT DC is similar to that on UCB DC and healthy adult DC. Comparisons of antigen-specific cells in FT and UCB demonstrated pp65-CTL frequencies were comparable, yet PR1- and WT1-CTL percentages were lower in UCB than in FT. PR1-specific cells, in contrast to pp65- and WT1-specific cells, were found at a higher frequency within CD8 single positive (SP) thymocytes versus CD4+CD8+ double positive (DP) cells, suggesting that PR1-specific SP thymocytes have a survival advantage relative to WT1- and pp65-specific SP thymocytes. In response to PR1 peptide-loaded T2 cells, DP PR1-CTL undergo apoptosis to a greater degree than SP PR1-CTL, implying that higher frequencies of SP PR1-CTL in FT could be due, in part, to a lower susceptibility of SP PR1-CTL to apoptosis. Our data suggest that PR1 expression by DC in the thymus is insufficient for complete central tolerance to PR1 and PR1-specific SP thymocytes may have a survival advantage over other self and viral antigen-specific thymocytes.
Effect of immunomodulatory polyphenols on innate lymphocyte responses involved in anti-tumor defense. (46.34)
Authors: Ramstead Andrew , Robison Amy , Jutila Mark 
Published: January 2023

Abstract
The anti-tumor effects of polyphenols have received considerable attention in recent years. The majority of research in this area has focused on the direct effect of these compounds on tumor cells, as well as their antioxidant activities. However, few studies have focused on the effect of these compounds on leukocyte responses involved in anti-tumor immunity. Two polyphenol extracts, which have been shown to have immunomodulatory and antitumor properties, are apple peel polyphenols (APP) and oenothein B (OB), a compound isolated from the Epilobium angustifolium plant. We have previously shown that these compounds are capable of stimulating innate lymphocytes, such as NK cells and γδ T cells. Since these innate lymphocytes play an important role in anti-tumor responses through several mechanisms, the effects of these polyphenol extracts on these cells was investigated further. We found that both APP and OB can modulate the expression of certain surface proteins and cytokines involved in tumor cell recognition and killing by innate lymphocytes, such as NKG2D and IFNγ. The effect of these polyphenols on the anti-tumor activity of innate lymphocytes and their importance is currently under investigation in both human cells and mouse models. Funded by NIH NCCAM PO1 AT004986.
CD8 T cell responses to Braf-mutated melanoma upon regulatory T cell depletion (46.37)
Authors: Steinberg Shannon , Zhang Peisheng , Byrne Katelyn , Bosenberg Marcus , Turk Mary Jo 
Published: January 2023

Abstract
A model for studying Braf-mutated melanoma in immunocompetent mice has recently been generated, in which melanocyte-specific induction of Cre recombinase leads to expression of mutant BrafV600E and deletion of the tumor suppressor Pten. Using these Braf/Pten mice on a C57BL/6 background, we are able to characterize the melanoma-antigen specific CD8 T cell responses by adoptively transferring CD8 T cells from Pmel-1 transgenic mice, whose T cell receptors are specific for the melanoma differentiation antigen gp100. As previous work in our lab has demonstrated the ability of CD4 cell depletion to eliminate regulatory T cells and drive priming of CD8 T cells in mice bearing B16 melanomas, we characterized the effects of Treg depletion in mice with Braf/Pten tumors. In these studies, we have shown that CD4 depletion enhances the frequency of melanoma antigen-specific CD8 T cells in the tumor draining lymph node and systemically. We have also found that while untreated Braf/Pten tumors have a low frequency of infiltrating CD8 T cells, Treg depletion allows for robust infiltration of CD8 T cells into the tumor. These studies provide evidence that while poorly immunogenic, autochthonous Braf-mutated tumors can prime CD8 T cells responses in the absence of regulatory T cells.
A role for Bcl-xL in CD1d-mediated Natural Killer T cell responses to B cells (46.39)
Authors: Subrahmanyam Priyanka , Webb Tonya 
Published: January 2023

Abstract
Lymphomas are a heterogeneous group of malignancies, primarily divided into Hodgkin's and non-Hodgkin's lymphomas (NHL). Unlike other cancers, the incidence of NHL is steadily rising. Natural Killer T (NKT) cells are innate-like lymphocytes that recognize glycolipid antigens in the context of CD1d, an MHC class I-like molecule. They have strong anti-tumor activity and respond by massive cytokine production and/or cytotoxicity. It is known that pro-survival factors are upregulated in B cell lymphomas, but their role in antigen processing and presentation remains unknown. The effect of Bcl-xL on CD1d-mediated antigen presentation was examined utilizing the well-characterized WEHI-231 B cell lymphoma cell line. Bcl-xL expression was modulated via genetic, pharmacologic and biological approaches. We found a concomminant increase in CD1d-mediated NKT cell responses following the induction of Bcl-xL; however, cell surface expression of CD1d molecules remained unchanged. Induction of Bcl-xL in primary B cells led to increased CD1d-mediated activation of NKT cells in response to exogenous antigens, resulting in increased Th1 not Th2 responses. Taken together, these data suggest that aberrant expression of Bcl-xL may act as a sentry system to alert the CD1d/NKT system to neoplastic transformation.