bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constitutive IL-10 production by normal and malignant B-1 cells is dependent on B cell receptor signaling (IRM10P.620)
Authors: Alhakeem Sara , McKenna Mary , Gachuki Beth , Wang Chi , Liu Jinpeng , Byrd John , Muthusamy Natarajan , Bondada Subbarao 
Published: January 2023

Abstract
The most common human leukemia is B-cell chronic lymphocytic leukemia (B-CLL), which can have immunosuppressive effects. CLL cells share multiple phenotypic markers with B-1 B cells such as their surface expression of CD5. This study identifies some functional similarities between B-1 and CLL cells. B-1 B cells have been shown to produce a high level of interleukin-10 (IL-10) constitutively and upon toll-like receptor stimulation, a characteristic property of regulatory B cells. Eμ-Tcl1 mice, which express the Tcl1 oncogene in a B cell specific manner, spontaneously develop B-CLL. We show that Eμ-Tcl1 mouse B-CLL cells also produce IL-10 constitutively. The constitutively produced IL-10 was not required for CLL survival in vitro. This study describes a novel role of B cell receptor (BCR) signaling pathway in constitutive IL-10 secretion by normal and malignant B-1 cells. Thus inhibition of Src family kinases, spleen tyrosine kinase (Syk) or Bruton’s tyrosine kinase (Btk), all of which are downstream of BCR, reduces constitutive IL-10 production by both normal and malignant B-1 cells. Analysis of a published microarray study showed that IL-10 levels were higher in peripheral blood of CLL patients than normal human blood samples, which correlated positively with STAT3 levels. Interestingly, we found that BCR signaling induced IL-10 production is independent of STAT3. Current studies are directed at understanding the mechanisms by which BCR signaling affects IL-10 production.
Regulation of the HSH2 adaptor protein turnover via an indirect NF-κB-dependent mechanism is involved in determining the nature of the class switched antibody response. (IRM10P.609)
Authors: VanValkenburg Arthur , King R. , Justement Louis 
Published: January 2023

Abstract
The Hematopoietic SH2 containing adaptor protein (HSH2) is differentially expressed in mature, peripheral B cell subpopulations, exhibiting low level expression in germinal center (GC) B cells versus high-level expression in B1 and marginal zone B cells. Studies have demonstrated an inverse relationship between its expression and the production of class-switched antibodies due to effects on terminal differentiation. Therefore, delineation of molecular mechanism that controls its expression is critical for understanding the class-switched antibody response. Studies demonstrated that upregulation of HSH2 following TNF family receptor or TLR-mediated signals, as well as its maintenance, requires NF-κB activity. Using both pharmacological and genetic approaches, it was shown that the canonical pathway is critical for maintenance of HSH2 expression. Inhibition of NF-kB selectively results in the rapid loss of HSH2, whereas actinomycin D and cycloheximide treatment do not. Analysis of the canonical pathway revealed that maintenance of HSH2 requires translocation of NF-κB to the nucleus. Because HSH2 mRNA levels are not altered under any conditions, it is hypothesized that NF-κB indirectly regulates the function of a short-lived protease that regulates HSH2 expression at the protein. These results reveal a potentially novel mechanism, in which NF-κB regulates HSH2 expression via one or more proteases and may represent a novel paradigm for controlling GC B cell function.
The role of Fli1 in lupus T cell function and nephritis in MRL/lpr lupus prone mice (IRM11P.634)
Authors: Nowling Tamara , Sundararaj Kamala , Thiyagarajan Thirumagal , Molano Ivan 
Published: January 2023

Abstract
The Ets factor Fli1 is implicated as a key modulator of lupus disease expression. Over-expressing Fli1 in healthy mice, results in the development of an autoimmune kidney disease similar to that observed in lupus. Lowering the global levels of Fli1 in two lupus mouse models significantly improved kidney disease and prolonged survival. We recently demonstrated that lowering the global levels of Fli1 in MRL/lpr lupus mice (Fli1+/-) reduced T cell activation and IL-4 production. This was likely a result of decreased glycosphingolipid (GSL) metabolism, specifically decreased Neuraminidase1 (Neu1) expression and activity and decreased levels of the GSL lactosylceramide (LacCer) in the Fli1+/- T cells. GSLs are a heterogeneous class of lipids in the sphingolipid family that play a role in the regulation of cellular processes. Neu1 is an enzyme that mediates the GSL catabolic pathway. Here we demonstrate that MRL/lpr Fli1+/- T cells have significantly decreased: 1) levels of CXCR3 message, 2) percentage that are CXCR3+, 3) migration to the kidney and 4) renal Neu1 and LacCer levels, which we showed are significantly elevated in nephritic mice and humans with lupus. IHC staining shows that increased LacCer levels co-localize with T cells in the glomeruli. Together, our data demonstrate that reducing Fli1 levels in lupus T cells partially normalizes GSL metabolism in the kidney that is likely due in part to a reduction in T cell activation and migration to the kidney.
Stat3 promotes kidney disease in Stat1-KO mice with lupus-like cGVHD (IRM11P.635)
Authors: Shao Wenhai , Gamero Ana , Zhen Yuxuan , Lobue Monica , Priest Stephen , Albandar Hazem , Cohen Philip 
Published: January 2023

Abstract
Lupus nephritis (LN) is one of the most serious manifestations of SLE with high incidence of morbidity and mortality. Opposing effects of activated Stat1 and Stat3 have been described for different diseases. Stat1 activation was reported upregulated in the kidney of lupus-prone mice with nephritis, while inhibition of Stat3 in the kidney attenuated kidney inflammation. The present study was undertaken to investigate the role of Stat1 in an experimental animal model of lupus. We induced bm12-B6 chronic graft-versus-host disease (cGVHD) in Stat1-KO and WT mice. WT mice developed anti-dsDNA autoantibodies starting at week 2 as expected, with a decline noted after week 4. In contrast, Stat1-KO mice exhibited a prolonged and significant increase of anti-dsDNA and anti-chromatin autoantibody responses compared to WT mice (week 4 to week 8). Enhanced IgG1 and IgG2b responses but absent IgG3 response were demonstrated in the sera of Stat1-KO mice as compared to WT mice given the same treatment. To our surprise, Stat1-KO mice developed severe nephritis starting at week 8. Three months after cGVHD-induction, 40% Stat1-KO mice were dead. Immunofluorescent staining of kidney sections from the cGVHD Stat1-KO mice revealed an enhanced glomerular Stat3 expression, which correlated with increased IL-6 expression. The observation that altered expression of Stat3 influences IL-6 expression in the glomeruli in this lupus model suggests possible molecular targets for treatment of LN.
Signal transducer and activator of transcription 3 (STAT-3) is a critical transcription factor in regulating germinal center IgE+ B-cell class switching
Authors: Dascani Paul Lorenzo , Ding Chuanlin , Yan Jun 
Published: January 2023

Abstract
A mutation in the Signal Transducer and Activator of Transcription 3 (STAT-3) has been linked to incidence of Autosomal Dominant Hyper Immunoglobulin E Syndrome (AD-HIES), a disease characterized by elevated serum IgE antibody and susceptibility to respiratory and skin infection. However, how this genetic mutation leads to the phenotype has not been fully understood. In this study we investigated the specific role of STAT-3 in the germinal center (GC), the site of B-cell proliferation and isotype switching. Through the use of CD2-Cre or CD19-Cre driven STAT-3 conditional knockout (cKO) mice in a Th2-type immunization model, we aimed to determine the specific cell subset(s) and signaling mechanism by which STAT-3 mediated isotype switching is regulated. We demonstrated in vivo and in vitro that CD2-Cre driven STAT-3 cKO mice showed elevated IgE and decreased IgG1 in the serum, and a reduction in GC formation. Within the GC, IgG1+ GC B cells were decreased while IgE+ GC B cells were more prevalent. Additionally, these mice exhibited reduced IgG1 and elevated IgE populations of antibody-producing plasma cells. Subsequent experiments using a CD19-Cre B-cell specific cKO mouse established this effect to be B-cell dependent. Our data also revealed other transcription factors, including Bcl-6 and Aicda, function as downstream signals of STAT-3 regulation. This model suggests a role for STAT-3 in regulating class switching of the GC B cells from the IgG1 to the IgE producing state, which may serve as a potential therapeutic target for treatment of AD-HIES and other immune disorders.
IL-1 uses distinct mechanisms to enhance CD8+ T cell expansion and differentiation.
Authors: Lee Ping-Hsien , Germain Ronald N , Paul William E 
Published: January 2023

Abstract
IL-1 is a potent proinflammatory cytokine with pleiotropic functions within and outside the immune system. We previously showed that IL-1 promotes antigen-specific CD8+ T cell expansion, effector function, and memory differentiation but the underlying mechanisms remain unclear. Here we report that IL-1 likely utilizes distinct pathways to drive CD8 T cell expansion and effector differentiation. Maximal expansion in the peripheral tissues (spleen, lung, and liver) was only achieved when IL-1 acted on both CD8 T cells and non-T cells, which involved cells of hematopoietic and non-hematopoietic origins. Although IL-1did not affect the abundance of CD8 T cells in the draining lymph nodes (dLNs), these IL-1-treated, dLN-derived CD8 T cells expanded more robustly than their control treated counterparts after getting into the tissues. IL-1 treatment also enhanced cytotoxic function, as evidenced by increased granzyme B expression, of CD8 T cells in both dLNs and tissues. This effect was mediated by IL-1R1 signaling in non-hematopoietic cells, especially vascular endothelial cells, but not in CD8 T cells or other hematopoietic cells. Furthermore, CD8 T cells were endowed with a T-bet(hi)Eomes(low) phenotype by IL-1 and did not succumb to apoptosis but rather generated better memory cells both quantitatively and qualitatively than did their control treated counterparts. Collectively, this study demonstrates novel and complex mechanisms used by IL-1 to enhance antigen-specific CD8 T cell responses, which may shed light into developing novel strategies for optimizing CTL responses in treating cancer and infectious diseases.
Expression of IL-15 is differentially regulated during lymphopenia depending on the method of induction
Authors: Schluns Kimberly S , Rivas Sarai , Stonier Spencer W , Colpitts Sara L , Anthony Scott M 
Published: January 2023

Abstract
Induction of lymphopenia has been exploited therapeutically to improve immune responses to cancer therapies and vaccinations. IL-15 has a well-established role in mediating lymphocyte responses after lymphodepletion; however, the mechanisms regulating these IL-15 responses are unclear. We report that cell surface IL-15 expression is upregulated during lymphopenia induced by total body irradiation (TBI), cyclophosphamide, or Thy1 antibody (Ab)-mediated T cell depletion, as well as in RAG−/− mice; interestingly, the cellular profile of surface IL-15 expression is distinct in each model. In contrast, soluble (s)IL-15 complexes were upregulated only after TBI and αThy1Ab. Analysis of cell specific IL-15Rα conditional knock out mice revealed that macrophages and DCs were important sources of sIL-15 complexes after TBI but provided a minimal contribution after αThy1Ab treatment. Unlike with TBI, induction of sIL-15 complexes after αThy1 Ab was sustained and only partially dependent on type I Interferons. The Stimulator of IFN Genes (STING) pathway was discovered to be a potent inducer sIL-15 complexes and was required for optimal induction of sIL-15 complexes in response to Ab-mediated T cell depletion and TBI suggesting products of cell death drive production of sIL-15 complexes after lymphocyte depletion. Lastly, we provide evidence that IL-15 induced by inflammatory signals in response to lymphodepletion drive lymphocyte responses as proliferation of memory CD8 T cells was strongly dependent on IL-15. Overall, these studies demonstrate that the form in which IL-15 is expressed, it’s kinetics and cellular source, and the inflammatory signals involved are differentially dictated by the manner in which lymphopenia is induced.
High fat diet influences T cell homeostasis and macrophage phenotype to maintain chronic inflammation
Authors: Singh Udai P , Mehrpooya Pegah , Marpe Bam , Singh Narendra P , Murphy E. Angela , Mishra Manoj K , Price Bob L , Nagarkatti Mitzi , Nagarkatti Prakash S 
Published: January 2023

Abstract
Over the past 20 years obesity has become a global health problem affecting the life expectancy of people at epidemic proportions. Obesity is characterized as a state of low-grade chronic inflammation that influences the development and progression of many chronic diseases. A unique role of T cells in adipose tissue has been shown in the initiation and regulation of the inflammatory cascade. However, the mechanisms responsible for the obesity-associated inflammation are not known. We investigated how high fat diet may influence homeostatic expansion of T cells, macrophage behavior and inflammation. High fat diet consumption alters the body weight, fat mass, and lean mass of mice when compared with those on a normal diet. The high fat diet increases the frequency of CD44+ and TCR αβ+T cells in the epididymal adipose tissues as compared with a normal diet. In mice consuming a high fat diet, we also found a significant increase in the frequency of CXCR3+ activated CD8T cells, CD8+KLRG1 cells and pro-inflammatory cytokines in mucosal and epididymal adipose tissues. High fat diet consumption resulted in greater than 2 fold changes in 85 gene and 142 miRs in epididymal adipose immune cells. Among these, ten inflammatory, obesity miRNAs and genes were validated by RT-PCR analysis. Pathway analysis also validated that differentially regulated miRNAs and gene target mRNAs are associated with T cell homeostatic expansion and macrophage function. Taken together, these results indicate that high fat diet modulates T cell homeostatic proliferation, macrophage phenotype, inflammatory miRNAs and genes to sustain inflammation. This study supports a key role of T cell homeostasis and macrophages to induce inflammation during high fat diet-induced obesity.
Natural Killer cell-mediated antibody-dependent cellular cytotoxicity towards red blood cells infected by Plasmodium falciparum
Authors: Arora Gunjan , Hart Geoffrey T. , Desai Sanjay A. , Long Eric O 
Published: January 2023

Abstract
In areas of high Plasmodium transmission, humans develop clinical immunity only after years of recurrent exposure. This naturally acquired immunity depends primarily on antibodies specific for parasite antigens. The underlying basis of this protective response remains unclear. In particular, the contribution of antibody-dependent cellular cytotoxicity (ADCC) to malaria immunity remains largely unexplored. Peripheral blood natural killer (NK) cells exhibit potent ADCC through FcγRIII (CD16) binding to antibody-coated target cells. We have developed sensitive and quantitative in vitro assays to evaluate outcome of infected red blood cells (RBC) incubation with NK cells. Without specific antibodies, NK cell-mediated natural cytotoxicity was undetectable towards both uninfected and infected RBCs. Addition of serum antibodies raised against human RBCs in immunized rabbits, however, produced NK cell-dependent lysis of both uninfected and infected RBCs. Rabbit serum antibodies specific for PfEMP1, an immunodominant P. falciparum variant antigen at the surface of infected RBCs, yielded selective lysis of infected RBCs. Plasma from malaria-immune individuals also triggered selective NK-mediated ADCC of infected RBCs. Finally, incubation of infected RBCs with NK cells in the presence of plasma from malaria-immune individuals inhibited P. falciparum growth, as determined by reinvasion of fresh, uninfected RBCs. Therefore, primary human NK cells can limit growth of bloodstream P. falciparum through specific ADCC-mediated lysis of infected RBCs.
Regulation of plasma cell differentiation, migration and class-switch by c-Myb and T-bet
Authors: Good-Jacobson Kim , Di Pietro Andrea , Tempany Jessica , Tarlinton David 
Published: January 2023

Abstract
Humoral responses are tailored to respond most effectively to the invading pathogen. To achieve this, long lasting, protective antibodies of an affinity and isotype appropriate for the immunising antigen or infecting pathogen are produced mainly within germinal centres (GC). Here, we detail the critical, interdependent roles of the transcription factors c-Myb and T-bet in regulating GC egress and plasma cell differentiation. Deletion of c-Myb in mature B cells led to aberrant up-regulation of plasma cell transcription factors within the GC. Indeed, a subset of cycling cells within the GC secreted antibody and were CD138+ Blimp-1-GFP+. T-bet-regulated genes were also modulated, resulting in significantly elevated serum IgG2c and CXCR3 expression on plasma cells despite a Th2-biased immunization with NP-KLH in alum. These aberrant plasma cells within the GC were no longer evident upon deletion of T-bet in c-Myb-deficient mice. Surprisingly, this interplay between transcription factor networks also occurred during a response to influenza infection, in which T-bet expression is a normal component of B cell responses in wild-type mice. Chromatin accessibility studies of the T-bet promoter revealed that wild-type GC B cells from flu-infected mice had an increase in accessibility in comparison to naïve B cells, as expected. In line with the cellular data, however, there was an even further increase in chromatin accessibility in c-Myb-deficient GC B cells. Therefore, c-Myb establishes a transcription factor network during an immune response that can modulate the transcriptional network of T-bet and subsequent coordination of GC egress with plasma cell differentiation.
Ubiquilin1 is uniquely required for cell cycle entry and proliferation downstream of B-cell receptor signaling.
Authors: Greer Alexandra , Abbas Alexander , Haley Benjamin , Peng Ivan , Roose-Girma Merone , Brown Eric J 
Published: January 2023

Abstract
Ubiquilins are a family of ubiquitin-like proteins thought to be chaperones for proteasome-bound ubiquitinated substrates. Recently, ubiquilins have been implicated in neurodegenerative disease, as UBQLN2 mutations cause ALS in some humans and variants in the ubiquitously expressed UBQLN1 have been associated with Alzheimers disease. The roles for ubiquilins in immune function, however, are unknown. In this study, we studied a mouse deleted for UBQLN1 to investigate the role of the gene in B-cell immunity. While adult knockout (ko) mice appeared generally healthy, we found a specific defect in peritoneal B1a cells and a dysregulation of the marginal zone/follicular B-cell proportions in the spleen. When activated in vitro, ko B-cells were profoundly hyporesponsive to BCR stimulation, but normally responsive to TLR4 stimulation. Despite a lack of proliferation downstream of BCR aggregation, ko B-cells had normal signal transduction and no significant changes in gene transcription at 4 hours post-stimulation. Instead, ko B-cells failed to accumulate cyclin D2 protein, a necessary event for cell proliferation, without any effect on BCR-stimulated upregulation of cyclin D2 mRNA. Moreover, knockdown of UBQLN1 via a doxycycline-inducible shRNA profoundly inhibited proliferation of BJAB, a Burkitt’s lymphoma line, in a rapid and reversible manner. These results demonstrate that UBQLN1 is required downstream of BCR stimulation for cell cycle entry by allowing accumulation of cyclin D2. We hypothesize that UBQLN1 may be involved in degradation of specific cell cycle checkpoint control proteins, or more generally the translation or stabilization of cell cycle control proteins upregulated upon certain mitogenic stimulation.
Identification of IFN-γ-producing innate B cells
Authors: Bao Yan , Cao Xuetao 
Published: January 2023

Abstract
Although B cells play important roles in the humoral immune response and the regulation of adaptive immunity, B cell subpopulations with unique phenotypes, particularly those with non-classical immune functions, should be investigated further. By challenging mice with Listeria monocytogenes, Escherichia coli, vesicular stomatitis virus, and TLR ligands, we identified an inducible CD11ahiFcγRIIIhi B cell subpopulation that is significantly expanded and produces high levels of IFN-γ during the early stage of pathogen infection. This subpopulation of B cells can promote macrophage activation via IFN-γ, thereby facilitating the innate immune response against intracellular bacterial infection. As this new subpopulation is of B-cell origin and exhibits the phenotypic characteristics of B cells, we designated these cells as IFN-γ-producing innate B cells. Dendritic cells were essential for the inducible generation of innate B cells from follicular B cells via CD40L-CD40 ligation, and increased Btk activation was found to be responsible for the increased activation of noncanonical NF-κB in innate B cells after CD40 ligation, with the consequent induction of additional IFN-γ production. The identification of this new population of innate B cells may contribute to a better understanding of B cell functions in anti-infection immune responses and immune regulation.
A novel molecule purified from Staphylococcus aureus mutant produces γδ T cell-mediated IL-17A in mice peritoneum and protects MRSA-derived skin abscess expansion
Authors: Lee Bok Luel , Khan Adnan , Lee Min-Ja , Sung Min-Young , Lee Bo-Ram , Yun Hye-Soo 
Published: January 2023

Abstract
Staphylococcus aureus, a commensal bacterium in human, causes a wide range of human diseases from soft tissue infections to lethal systemic infections. But, immune-competent people are highly resistant to these diseases, indicating that unknown host defense response(s) can protect host. An effective immune response to S. aureus requires a rapid activation of innate immunity in the shape of γδ-T cells mediated IL-17 production for bacterial clearance. We hypothesized that an unidentified staphylococcal-cell wall derived molecule(s) that can activate host innate γδ-T cells is generated after S. aureus infection in healthy people. To purify this molecule(s) in mice, we generated 11 different S. aureus mutant strains, in which genes involved in staphylococcal cell wall components bio-syntheses were mutated. The mutant cells were acetone-treated to inactivate and extract toxic molecules, and then injected intra-peritoneal cavity of mice. When peritoneal lavage fluid collected 5 hr after injection was examined which mutant bacteria can produce IL-17A, three mutants produced IL-17A. To purify active fractions capable of γδ T cell-mediated IL-17A production, acetone-treated mutant bacterium was solubilized with two different peptidoglycan hydrolyzing enzymes. Then, active molecules were purified to homogeneity on ion-exchange columns. By pre-injection of purified molecule or acetone-treated mutant bacteria, the expansion of USA 300 MRSA-mediated skin abscess was inhibited, leading to a lower bacterial numbers and decrease of abscess lesion size at the site of infection. These results suggest that a novel molecule producing γδ T cell-derived IL-17A in peritoneum protected MRSA-derived skin abscess expansion in mice.