bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of cross priming and anti-tumor immunity in vivo (107.2)
Authors: Shen Lianjun , BelleIsle Janice , Rock Kenneth 
Published: January 2023

Abstract
Cross priming plays an important role in immune surveillance against invading pathogens and cancers. The underlying mechanisms and regulation of this process, especially in vivo, are still not fully understood. The cross priming process in vivo is regulated and influenced by a number of factors at several levels. One factor is the state of the antigen donor cells. Another component is the contribution of innate immune receptors (TLR, CLR and NLR). We find that although the innate adaptor MyD88 is dispensable for cross priming of primary CD8 T cell responses, it is essential to generate long lasting anti-tumor immunity. Yet another factor that has been suggested is the participation of CD8α+Clec9a+ dendritic cells in cross presentation. However, we find that the primary CTL response primed by cell-associated antigen is largely unaffected or marginally compromised in mice lacking the CD8α+Clec9a+ DC subset, suggesting that other types of APCs also make a significant contribution. Taken together, many factors are involved in cross priming and its outcome.
Mapping a dynamic innate immunity protein interaction network regulating type I interferon production (108.2)
Authors: Li Shitao , Wang Lingyan , Berman Michael , Dorf Martin 
Published: January 2023

Abstract
We use co-immunoprecipitation and mass spectrometry to identify antiviral signaling networks which regulate innate immune responses. Fifty-eight baits were associated with 260 interacting proteins forming a Human Innate Immunity Interactome of 401 unique interactions; 21% of interactions were remodeled following RNA, DNA, or LPS stimulation. Overexpression and depletion analyses identified 22 novel genes which regulate NF-kB and ISRE reporter activity, viral replication, or virus-induced interferon production. The innate immune interactome provides a dynamic physical and regulatory network which serves as a foundation for mechanistic analysis of antiviral signaling and links innate immunity with other cell processes.
Role of BST-2/Tetherin in Hepatitis C Virus Infection (108.6)
Authors: Amet Tohti , Grantham Ayslinn , Byrd Daniel , Hu Sishun , Yu Qigui 
Published: January 2023

Abstract
Bone marrow stromal cell antigen 2 (BST-2, also known as tetherin/CD317/HM1.24) is an interferon (IFN)-inducible membrane protein with a potential role in innate immunity against virus infection. BST-2 has recently been identified as a host restriction factor for diverse families of enveloped viruses including retroviruses, filoviruses, arenavirus and herpesvirus. In theory, any lipid-enveloped virus could be restricted by BST-2. However, BST-2 antiviral activity against hepatitis C virus (HCV), a lipid-enveloped RNA virus, has not yet been studied. Here we demonstrate that human hepatic cell line Huh7.5.1 expresses a low level of BST-2. However, robust expression or induction of BST-2 in Huh7.5.1 can be elicited upon stimulation with IFN-α, IFN-γ or both. Over-expression of BST-2 by either interferon treatment or BST-2-expressing plasmid DNA transfection suppressed culture-type infectious HCV (JFH1) production in Huh7.5.1 cells. In addition, shRNA-mediated depletion of endogenous BST-2 resulted in enhanced HCV production. Our results have demonstrated a previously unknown anti-HCV activity of BST-2, and have also identified BST-2 as a host restriction factor against HCV infection. These results indicate that the induction of BST-2 in hepatic cells could be one of the mechanisms by which current HCV standard therapy (IFN-α plus ribavirin) achieves a sustained virological response. Our data also point out a novel therapeutic strategy to control HCV infection.
Role of innate signaling pathways in the regulation of antiviral IgG2c responses (108.9)
Authors: Raval Forum , Lien Egil , Pitha Paula , Szomolanyi-Tsuda Eva 
Published: January 2023

Abstract
Long-term antibody responses provide protection from re-infection and recrudescence of persistent viruses. IgG2a/c is a predominant immunoglobulin isotype in most virus infections. Using a polyomavirus (PyV) mouse model, our lab has shown that MyD88 KO mice generate low levels of virus-specific IgG after the acute phase of infection, have reduced numbers of long-lived plasma cells and make very low levels of IgG2c, but normal levels of IgG1. Investigating the pathways upstream and downstream of MyD88, here we show that in response to PyV infection (i) Unc93B1 mutant mice, which are triple deficient in TLR3, 7 and 9 have diminished IgG2c, but normal IgG1 responses; (ii) TLR9 KO and TLR7 KO mice do not have greatly altered IgG isotype responses as observed in MyD88 KO mice or the Unc93B1 mutant mice, suggesting that these receptors play a redundant role; and (iii) mice lacking IRF5, a transcriptional regulator downstream of MyD88, have greatly diminished IgG2c and normal IgG1 responses, similar to MyD88 KO mice. The isotype switching defect observed in IRF5 KO mice is B cell intrinsic, as transfer of IRF5 KO B cells and WT T cells into RAG KO mice results in diminished antiviral IgG2c secretion compared to mice reconstituted with B6 B and T cells. Therefore, our studies suggest that TLR7/9-MyD88-IRF5 pathways in B cells play an essential role in the generation of IgG2a/c responses to virus infection.
Prostaglandin E2 augments p53 mRNA transcription and protein expression in activated human B lymphocytes (109.12)
Authors: Haque Shabirul , Nieto Jennifer , Chiorazzi Nicholas , Mongini Patricia 
Published: January 2023

Abstract
p53 suppresses malignancy by controlling the cell cycle and apoptosis. COX-2 and downstream prostaglandin E2 (PGE2) are upregulated in malignancies and activated B cells; in the latter, PGE2 augments or diminishes survival and can elevate activation-induced cytosine deaminase (AID) and isotype-switching. Because p53 and COX-2 are co-expressed in B cells, we tested if co-expression was mechanistically linked. PGE2 was added to cell density-limiting cultures of purified B2 cells from human tonsil/spleen, pre-activated with surrogate C3dg-coated antigen + IL4 + BAFF. p53 protein was monitored by intracellular staining of CFSE-labeled cultures and p53 mRNA by q-RT-PCR. Pulses of PGE2, or the EP2 receptor-specific analog Butaprost, at d2 significantly augmented p53 protein only in d5 cycling blasts; this was preceded by elevations in p53 mRNA. Consistent with greater expression of EP2 in cycling blasts, PGE2-promotion of p53 mRNA synthesis occurred only in the latter. Studies involving Actinomycin D indicate that PGE2 augments p53 mRNA synthesis without notably affecting mRNA stability. Because transcriptionally active genes are more prone to mutation, our data suggest that autocrine or paracrine PGE2 may promote p53 mutation in activated B cells.
Congenital B cell lymphocytosis linked to a novel germline CARD11 mutation (109.13)
Authors: Snow Andrew , Xiao Wenming , Chaigne-Delalande Benjamin , Pittaluga Stefania , Stinson Jeffrey , Matthews Helen , Lu Wei , Schmitz Roland , Jhavar Sameer , Jing Huie , Su Helen , Staudt Louis , Lenardo Michael 
Published: January 2023

Abstract
Nuclear Factor-kappa B (NF-κB) governs the transcription of many genes for normal lymphocyte functions, but constitutive NF-κB activation is most often associated with B cell malignancy. Using high-throughput whole transcriptome sequencing, we recently investigated a family with a unique, hereditary polyclonal B cell lymphocytosis. Here we report our discovery of a novel, germline heterozygous missense mutation (E127G) in affected patients in the gene encoding CARD11, a lymphocyte-specific scaffolding protein required for antigen receptor (AgR)-induced NF-κB activation in both B and T lymphocytes. Similar to somatic, gain-of-function CARD11 mutations described in diffuse large B cell lymphoma, E127G CARD11 spontaneously oligomerizes and activates NF-κB when upon ectopic expression in lymphoid cell lines. Primary lymphocytes from these patients also display evidence of CARD11 aggregation and constitutive NF-κB activity. In contrast to B cells, however, we observed that E127G CARD11 contributes to patient T cell hyporesponsiveness upon AgR stimulation, even though the proximal CARD11-associated signaling machinery is highly similar between B and T cells. Our findings suggest that an activating, germline CARD11 mutation can selectively induce B cell expansion and preferentially predispose to B cell malignancy without perturbing T cell homeostasis.
Processing of AID-induced uracils in distinct cell cycle phases (109.8)
Authors: Jolly Chris , Sharbeen George , Yee Christine , Smith Adrian 
Published: January 2023

Abstract
Immunoglobulin (Ig) affinity maturation requires the enzyme AID, which converts cytosines in Ig genes into uracils. This alone produces C:G to A:T transition mutations. Processing of U:G base pairs via UNG2 or MutSα generates further point mutations, predominantly at G:C or A:T base pairs, respectively, but it is unknown why processing is mutagenic. We aimed to test whether the cell cycle phase of uracil processing determines fidelity. Accordingly, we ectopically restricted UNG2 activity in vivo to pre-defined cell cycle phases by fusing a transduced inhibitor peptide to cell cycle regulated degradation motifs. We conclude that excision of AID-induced uracils by UNG2 occurs exclusively in G1-phase, leading to mutation alongside predominantly correct repair. Surprisingly, UNG2 does not seem to process U:G base pairs at all in Ig genes undergoing replication. Preliminary data indicates that processing of AID-induced uracils via MutSα is also cell cycle regulated.
The asymmetric partitioning of mTORC1 activity during cell division facilitates CD8+ effector versus memory T cell generation (110.18)
Authors: Pollizzi Kristen , Delgoffe Greg , Lo Ying-Chun , Patel Chirag , Powell Jonathan 
Published: January 2023

Abstract
CD8+ T cells are an essential component of the adaptive immune response, generating both effector cells necessary for clearance of acute infection and long-lived memory cells primed to provide a rapid response upon secondary infection. The mechanism by which CD8+ T cell effector versus memory differentiation arises remains unclear. Here we show that upon antigen stimulation, mTORC1 activity is asymmetrically partitioned during cell division. Cells fated to become effector cells show high mTORC1 activity, while memory precursors have low mTORC1 signaling. These results correlate with experiments generated from T cell specific knockouts of Rheb, an mTORC1 activator, and TSC2, an mTORC1 negative regulator. CD8+ T cells deficient in mTORC1 activity fail to differentiate into effector cells, but retain memory characteristics such as surface marker expression and longevity in vivo. In contrast, CD8+ T cells with hyper-active mTORC1 signaling have potent effector capabilities both in vitro and in vivo but retain the phenotype of terminally differentiated effector cells incapable of transitioning into memory, being short lived and unable to proliferate upon secondary infection. Our data highlight a role of mTOR as a critical regulator in determining CD8+ T cell fate. Further, we suggest that the generation of CD8+ T cell effector vs. memory lineages is dependent upon the asymmetric distribution of mTORC1 signaling during cell division.
IL-1 signals regulate effector CD8 T cell expansion and memory differentiation (110.23)
Authors: Sarkar Surojit , Penny Laura , Khan Arif , Kalia Vandana 
Published: January 2023

Abstract
Inflammation is a critical bridge between innate and adaptive immunity. However, how CD8 T cells sense and get programmed by inflammation remains to be clearly understood. The role of the prototypic pro-inflammatory cytokine, Interleukin-1 (IL-1), in regulating CD8 T cell responses during acute infections is not known. Our studies demonstrated a necessary requirement of IL-1 signals in programming the initial expansion of CD8 T-cells following antigenic encounter. The absence of IL-1 signals resulted at least 10-fold lower Ag-specific effector and memory cells. Moreover, effector functions such as cytotoxicity and polyfunctionality (co-production of IFN-γ, TNF-α and IL-2) were also compromised in the absence of IL-1 signaling. Together, this defect in CD8 T-cell expansion and effector differentiation led to delayed pathogen clearance. In line with this, hallmark memory properties of recall proliferation and homeostatic maintenance were also significantly compromised in the absence of IL-1 signaling. While, IL-1 signals were essential for programming CD8 T-cell expansion, differentiation of memory cells intrinsically from effector cells was not affected. Collectively, these data demonstrate a critical and novel role of IL-1 signaling in promoting CD8 T cell expansion and effector differentiation, and in programming functional memory responses. This knowledge will have a major impact on our strategy of adjuventing vaccines that will effectively program protective immunity.
Enhanced memory development in mice by aptamer targeted mTORC1 inhibition in CD8+ T cells (110.3)
Authors: Berezhnoy Alexey , Castro Iris , Malek Thomas , Gilboa Eli 
Published: January 2023

Abstract
Recent studies have highlighted the importance of immunological memory in mediating protective immunity in chronic infectious diseases and cancer. Inhibition of intracellular mediators of T cell differentiation with pharmacological agents was shown to promote memory differentiation in mice. However, given their often pleiotropic effects, non-targeted administration of pharmacological agents could compromise their immune promoting properties. We have shown that a CD8+ T cell targeted 4-1BB aptamer -raptor siRNA conjugate downregulated mTORC1, while preserving mTORC2, activity in 60% of adoptively transferred OVA-primed OT-I cells while sparing host cells. Both rapamycin and aptamer-siRNA conjugate led to the development of an enhanced proliferative recall response. However, the rapamycin-generated memory cells were defective in their in vivo cytotoxic effector functions which correlated with reduced perforin expression. Likewise, rapamycin or aptamer-siRNA conjugate treatment enhanced the in vivo differentiation of gp100-primed Pmel-1 cells into memory cells. Consistent with a cytotoxic defect in the rapamycin-generated memory cells, the rapamycin-treated mice were not able to inhibit a challenge with gp100-expressing B16 melanoma tumor cells. These observations support the premise that in vivo cell-targeted inhibition of mTOR, and conceivably other mediators of T cell differentiation, will circumvent undesirable effects of non-targeted inhibition by pharmacological agents.
T Cell Factor-1 and beta-catenin regulate the development of memory-like CD8 thymocytes (110.6)
Authors: Sharma Archna , Chen Qinghua , Nguyen Trang , Yu Qing , Sen Jyoti 
Published: January 2023

Abstract
In addition to conventional alpha-beta T cells, recent studies have demonstrated the presence of a subset of CD8 single positive (SP) mature thymocytes, referred to as memory-like or innate-like thymocytes that acquire effector functions in the thymus as a result of the maturation process. These cells have been described in mice with mutations in KLF2, Itk, CBP genes and SLAM family members and in non-mutant Balb/c mice in response to IL-4 produced by thymocytes. Here, we demonstrate that enhanced function of transcription factors T Cell Factor (TCF)-1 and beta-catenin regulate the frequency of IL-4 producing thymocytes that promote the generation of Eomes-expressing memory-like CD8 thymocytes in trans. By contrast, TCF1-deficient mice show a paucity of these cells demonstrating an essential requirement of TCF1 for the generation of Eomes-expressing memory-like CD8 thymocytes. Generation of TCF1 and beta-catenin-dependent memory-like CD8 thymocytes requires the expression of IL-4 and IL-4 receptor. CD8 memory-like T cells migrate to the periphery and are functional. Thus, TCF1 and beta-catenin regulate the generation of memory-like CD8 T cells in the thymus in a non-cell intrinsic manner.
Mef2c is required for the development of B cells at multiple points during B cell maturation and for the expression of B cell-specific surface proteins (111.12)
Authors: Roundy Kirstin , Debnath Irina , Pioli Peter , Weis Janis , Weis John 
Published: January 2023

Abstract
The Mef2 family transcriptional regulator Mef2c is highly expressed in maturing bone marrow and peripheral mature B cells. To evaluate the role of this transcription factor in developing B cells, we generated a B cell specific conditional deletion of Mef2c using the Mb-1-Cre transgene that is expressed during the early stages of immunoglobulin rearrangement. Young mice possessing this defect demonstrated a significant impairment in B cell numbers in the bone marrow and spleen. This phenotype was evident in several B cell subsets; however, this deficit diminished with B cell maturation and migration to peripheral B cell compartments. The absence of Mef2c also produced a unique CD23- B cell subset that persisted with maturation and could not be induced to express CD23 in cultured, differentiated B cells. Genome wide expression analysis of immature and mature B cells lacking Mef2c indicated altered expression of several key regulatory factors for B cell function including Ciita, Fcer2α, Cr1/Cr2, and Tnfsf4. The altered expression of these genes was confirmed by transcript analysis and flow cytometry while the specificity of Mef2c involvement was confirmed with ChIP analysis. In summary, the data presented here point to a role for Mef2c as a key transcriptional regulator during multiple stages of B cell development and demonstrate its ability to control the expression of a number of proteins required for appropriate mature B cell functions.
Mi-2/NuRD chromatin remodeling complexes maintain transcriptional attenuation during B cell development (111.17)
Authors: Hagman James , Ramirez Julita , Dege Carissa , Eshleman Emily , Musselman Catherine , Kutateladze Tatiana 
Published: January 2023

Abstract
Our laboratory has previously demonstrated the importance of epigenetic mechanisms for activating mb-1 (Ig-α/Cd79a) promoters in B cell progenitors. In response to the transcription factors EBF1 and Pax5, mb-1 promoters undergo stepwise epigenetic remodeling prior to their transcription. This regulation includes at least two components: enhancement of chromatin accessibility and the loss of CpG methylation. These mechanisms require SWI/SNF chromatin remodeling complexes. In opposition to SWI/SNF, Mi-2/NuRD complexes provide a barrier to activation in the absence of transcriptional activators. To better understand how Mi-2/NuRD controls transcription, we developed an in vitro cell system that allows for depletion of endogenous Mi-2β(CHD4), the catalytic component of Mi-2/NuRD, concurrent with exogenous expression of wild type or mutated Mi-2β and transcriptional activators in B cells. Our data demonstrate that multiple domains in Mi-2β are required for its association with chromatin and transcriptional attenuation. Furthermore, the data suggest that Mi-2/NuRD complexes bind and stabilize DNA methylation. Knockdowns of methyl-binding proteins in Mi-2/NuRD complexes confirmed their importance for functions of Mi-2/NuRD. These data suggest a hierarchy of function in which recruitment or exclusion of chromatin remodeling complexes by transcription factors including EBF1 regulates gene expression during B cell ontogeny.
Pyruvate kinase M2 plays distinct roles in hematopoietic stem cells and leukemia (111.19)
Authors: Wang Ying-Hua , Scadden David 
Published: January 2023

Abstract
It has been realized that different cell states employ different metabolic modes. Whether metabolism is a determinant of cell state is unclear, but studies in cancer suggest that altering metabolic activity can modify cellular function. Cancer cells metabolize glucose through glycolysis even in the presence of oxygen, a phenomenon called Warburg effect. Normal somatic cells thought to also preferentially use glycolytic metabolism are tissue stem cells, particularly the hematopoietic stem cells (HSC) resident in the hypoxic microenvironment of the bone marrow. Recently the molecular basis for Warburg effect in cancer cells has been identified as due to a specific isoform of pyruvate kinase M2 (PKM2). Interestingly, HSC also express PKM2. Using a mouse strain that allows conditional deletion of PKM2, we observed that PKM2 depletion enhances normal HSC function as revealed by a competitive transplantation assay. The altered cellular function is accompanied with decreased glycolysis and increased oxidative phosphorylation specifically in the primitive stem/progenitor cell population. Notably however, PKM2 deletion markedly disadvantages disease development in mouse models of both acute and chronic myeloid leukemia. Such a distinction in response between normal and malignant cells is unprecedented to our knowledge and may offer a highly unique opportunity to advantage normal while disadvantaging malignant cells of the hematopoietic lineage by targeting a single metabolic enzyme.
CD27 expression patterns on human developing B cells in fetal and adult tissues (111.27)
Authors: Su Kuei-Ying , McWilliams Laurie , Liang Xiaoe , Floyd Serina , Amos Joshua , Moody M. , Kuraoka Masayuki , Kelsoe Garnett 
Published: January 2023

Abstract
CD27 is an accepted marker for memory B cells in humans. However, CD27 expression was recently demonstrated on substantial populations of human B cells in cord blood and fetal liver (FL), tissues that contain few if any memory B lymphocytes. In addition, CD27 expression was recently proposed to identify natural B cells, the human counterpart of murine B-1 B cells. These observations led us to explore the characteristics of human, CD27+ B cells, and particularly developing B cells. Comparing B cells from FL, cord blood, and adult bone marrow (BM), we found CD27 expression as early as the pro-B cell stage. Moreover, the frequency of CD27+ pro-B cells was higher in FL than in BM. Expression of TdT, RAG1 and VpreB in CD27+ pro-B cells was similar to conventional, CD27- pro-B cells, confirming their identity as B-lineage progenitors. Developmentally immature CD27- and CD27+ B cells showed no significant differences in VH gene usage, VH mutation frequencies, or CDRH3 length, excluding the possibility of contamination by memory B cells. Interestingly, when placed in an in vitro culture system optimized to support the maturation of human fetal pro-B cells and murine B-1 B cells, CD27+ pro-B cells differentiated into IgM+ immature and transitional B cells significantly more efficiently than did autochthonous CD27- pro-B cells. In conclusion, we have demonstrated functional CD27+ pro-B cells in FL and BM that may identify a predominantly fetal, B-cell lineage in humans.