bluuebunny/crossref_metadata_2025_split huggingface dataset:
H3K27me3-specific demethylases modulate B cell development and differentiation
Authors: Kania Anna , Scharer Christopher D. , Price Madeline J , Haines Robert Richard , Alexander-George Lou-Ella , Boss Jeremy 
Published: January 2023

Abstract
B cell terminal differentiation into antibody secreting plasma cells (ASC) must be properly regulated to ensure robust humoral immune responses against foreign but not self-antigens. While the role of transcription factors in this process is well-established, there is also a growing appreciation of the epigenetic regulation of B cell differentiation. The histone modification H3 lysine 27 trimethylation (H3K27me3) is associated with a repressive chromatin state and gene silencing and is highly dynamic during B cell differentiation. EZH2, the enzyme that deposits H3K27me3, is required for proper B cell development, as well as germinal center and ASC formation. However, the role of active demethylation of H3K27me3 by the two demethylases UTX and JMJD3 in B cells is still to be elucidated. To determine the requirements for these enzymes in B lymphocytes, we crossed Utxfl/flJmjd3fl/flmice onto Cd19Cre/+background (dKO mice). In dKO mice, we observed a significant increase in T2 transitional and marginal zone B cells in the spleen and a reduction in circulating mature B cells in the bone marrow. To determine the role of UTX and JMJD3 in T cell dependent B cell responses, we infected CreCtrl and dKO mice with PR8 influenza virus. Fourteen days post infection, we observed a modest increase in GC B cells and skewing in the GC polarity in dKO mice. RNA-seq of CreCtrl and dKO GC B cells revealed that majority of differentially expressed genes (DEGs) were downregulated in the absence of UTX and JMJD3. Furthermore, a subset of down-DEGs were enriched for H3K27me3 in dKO supporting the role of UTX and JMJD3 in promoting gene. expression. Taken together, these data place H3K27me3 demethylases as critical enzymes that regulate the epigenetic dynamics of B cell fate.
Elucidating the nature of long-lived plasma cell precursors
Authors: Vijay Godhev Kumar Manakkat , Chawla Amanpreet Singh , Singh Harinder 
Published: January 2023

Abstract
Plasma cells (PCs) are terminally differentiated B cells that secrete protective antibodies and serve as a source of long-term humoral memory. PC precursors appear to be generated late in the germinal center B cell response in the spleen and migrate to the bone marrow (BM) to differentiate into PCs. However, the developmental and molecular mechanisms that control the generation, migration and differentiation of precursors of long-lived PCs (LLPCs) remain to be elucidated. In order to identify and characterize the precursors of LLPCs we established a novel adoptive transfer system. C57Bl/6J mice were immunized with NP-KLH along with LPS and alum. Post-immunization, splenic CD138+ cells were isolated on days 21, 28, 35 and 42 and then adoptively transferred into the B cell deficient μMT mouse strain. Sustained NP-specific IgG1 responses were observed in the μMT recipients, with a peak following adoptive transfer of day 35, CD138+ cells. The adoptively transferred cells were demonstrated to contain LLPC precursors as they generated NP-specific IgG1+ antibody secreting cells (ASCs) in the BM that were sustained for over 2 months following transfer. These results directly demonstrate that precursors of LLPCs arise between days 28 to 42 post-immunization. Genomic analyses of LLPC precursors using scRNA-seq and Ig profiling is being used to uncover molecular mechanisms that regulate their generation and differentiation.
A Single Administration of Fc-Fused Recombinant Human IL-7 Induces Expansions of T Lymphocytes in Healthy Adult Volunteers
Authors: Kim Sojeong , Choi Dong-Hoon , Heo MinKyu , Lee Byung Ha , Yang Se-Hwan , Sung Young Chul , Lee Howard , Shin Eui-Chul , Park Su-Hyung 
Published: January 2023

Abstract
Interleukin-7 (IL-7) is a cytokine that plays important roles in the development and homeostasis of T lymphocytes, which supports its application to reconstruct T cell populations in patients with a low lymphocyte count caused by various reasons such as hematopoietic stem cell transplantation or intensive chemotherapy. We investigated the effects of Fc-fused recombinant human IL-7 (rhIL-7-Fc) on T cell immunity in 24 healthy volunteers, who received a single subcutaneous (20 and 60 mg/kg) or intramuscular (60 mg/kg) dose of rhIL-7-Fc. We observed a significant increase in the number of CD8 and CD4 T cells after rhIL-7-Fc administration, the peak of which was seen on days 14–21 post dose. Importantly, single administration of rhIL-7-Fc increased the number of all subsets (naïve, EM, CM) of both CD8 and CD4 T cells, coupled with an enhanced expression of Ki-67, a marker of T cell proliferation. Furthermore, the numbers of other immune cells such as NK cells, NKT cells and γδ T cells were also increased after rhIL-7-Fc administration, whereas the number of B cells was transiently decreased on 7–14 days after rhIL-7-Fc administration and gradually recovered to the pre-treatment value. In conclusion, our results indicated that rhIL7-Fc’s potential immunomodulatory role can be further tested in humans to develop it as a beneficial agent to treat patients with a low lymphocyte count.
Themis integrates T cell receptor and cytokine signals in CD8+ T cells
Authors: Gascoigne Nicholas R J , Brzostek Joanna , Zhao Xiang , Fu Guo , Chen Elijah W. , Mehta Monika 
Published: January 2023

Abstract
T cell receptor (TCR) signaling controls T cell development in the thymus and T cell functions in the periphery. Themis is a T-cell lineage-specific protein with a critical role in T cell development, where it regulates TCR signal strength though modulation of Shp1 phosphatase activity. The role of Themis in mature peripheral T cells is unknown. To address this, we generated Themis conditional knockout (cKO) mice, with post-selection Themis deletion mediated by distal Lck-Cre. The cKO mice have reduced CD8+ T cell numbers. Themis-deficient CD8+ T cells on the OT-I TCR transgenic background show normal functional responses to agonistic pMHC ligands of different affinities. However, Themis-deficient OT-I CD8+ T cells have reduced cell surface expression of CD5 and increased cell surface expression of CD8, suggesting decreased signal from self pMHC. Moreover, cKO OTI CD8+ T cells display severe reduction in lymphopenia-induced (homeostatic) proliferation in vivo, as well as reduction in proliferative responses to low affinity pMHC and pro-inflammatory cytokines in vitro. Signals from low affinity pMHC and cytokines synergistically induce phosphorylation of Akt, metabolic changes, and induction of c-Myc in CD8 T cells. This does not occur in the absence of Themis. Themis performs these functions through the phosphatase Shp1, as double deletion of Themis and Shp1 in peripheral T cells rescues the CD8+ T cell maintenance. This work shows a novel role for cytokines and very low affinity pMHC in altering cellular metabolism to drive CD8+ T cell proliferation. It also demonstrates that Themis and Shp1 act in concert to integrate T cell receptor and cytokine signals.
STAT4 programs CD103− tissue-resident memory cells during infection
Authors: Bergsbaken Tessa , Fung Helen , Wilson Nicolette , Teryek Matthew 
Published: January 2023

Abstract
Tissue-resident memory (Trm) CD8+ T cells represent a distinct population of memory T cells that are maintained independently of the circulation and are positioned to respond rapidly to reinfection of the tissue. Using the bacterial pathogen Yersinia pseudotuberculosis (Yptb), we identified two distinct intestinal CD8+ Trm populations that are differentiated by their expression of the integrin CD103. Proximity of T cells to areas of inflammation within the intestinal tissue regulated Trm differentiation, with IL-12 leading to increased numbers of CD103− Trm cells. Therefore, we examined the role of the transcription factor STAT4 in the programming of this Trm subset. During infection, both wild-type and Stat4−/− T cells expanded and entered the intestinal tissue at similar rates. Stat4−/− T cells localized to areas of inflammation along with wild-type cells, but failed to express CD103− Trm signature genes. After infection, Stat4−/− CD103+ intestinal Trm cells formed a stable memory population; however, the number of Stat4−/− CD103− Trm cells was significantly reduced relative to wild-type Trm cells. We also observed impaired persistence of Stat4−/− CD103− Trm cells in other tissues with prominent CD103− Trm populations, including the liver, colon, and mesenteric adipose. RNA-seq analysis of wild-type and Stat4−/− CD103− Trm populations was used to identify genes required for the maintenance of this Trm subset. This work has identified STAT4 as a regulator of CD103− Trm differentiation and maintenance across multiple tissues, and these results will help identify strategies to maximize the number and persistence of Trm cells during vaccination and allow us to address the role of Trm heterogeneity in tissue-specific immunity.
STAT3 in T cells Regulates Protective Capacity of Hybrid Type 1/Follicular helper T cells in Persistent Mouse Malaria Infection
Authors: Stephens Robin , Dent Alexander L. , Carpio Victor H. 
Published: January 2023

Abstract
In infection with Plasmodium spp., IFN-γ+ T helper (Th)1 cells control peak parasitemia, while antibody and IL-21+ T follicular helper (Tfh) cells effect final clearance. However, we show that hybrid Th1/Tfh cells (IFN-γ+IL-21+CXCR5+), reported to be sub-optimal Th cells and to inhibit Germinal Centers (GC), dominate the immune response to P. chabaudi infection. Th1/Tfh expand but plateau at low levels while GC form, with GC-Tfh numbers stable throughout. To understand molecular mechanisms of differentiation of Th1/Tfh, mice deficient in several transcription factors targeted in T cells were infected. We found that T cell-intrinsic Bcl6 and Blimp-1 regulated CXCR5 and IL-10 expression in Th1/Tfh cells. Bcl6, Blimp-1 and STAT3 all dampen T-bet expression. However, neither of the Signal Transducer and Activator of Transcription (STAT) proteins known to regulate T-bet expression, STAT4 or STAT1, were required for IFN-γ production by Th1/Tfh. On the other hand, T cell deficiency of the Tfh-promoting transcription factor, STAT3, reduced antibody while non-hybrid Th1 cells increased and mice were fully protected from re-infection. Conversely, deficiency in T-bet, reduced Th1 differentiation, including dramatically reducing production of IFN-γ and specific antibody of the IgG2b isotype, and showed reduced control of re-infection. We have previously shown that few committed Th1 memory cells are generated in Plasmodium infection, importantly here the increase in Th1 features in STAT3-deficient T cells can improve control of reinfection. In summary, a flexible T cell population regulates each effector function with multiple transcription factors, providing plasticity to allow continuous responsiveness to prolonged infection.
Ex vivo analysis of Plasmodium falciparum-specific B cell responses to natural malaria infection in children and adults
Authors: Hopp Christine , Andrews Sarah , Chambers Michael , Leggat David J , Traore Boubacar , Pierce Susan K , McDermott Adrian B , Crompton Peter D 
Published: January 2023

Abstract
In naturally acquired immunity to malaria, antibodies that reliably protect are only acquired after years of repeated Plasmodium falciparum (Pf) infections. We have shown in Mali that this inefficiency in humoral immunity to malaria is associated with a large expansion of CD21loCD27− ‘atypical’ MBCs. The function of atypical MBCs remains elusive, as they exhibit altered B cell receptor (BCR) signaling and when activated fail to secrete cytokines and antibodies. We set out to study whether atypical or classical B cells are recruited into the immune response to a febrile malaria infection: using Pf antigen probes, we characterized PfAMA1/PfMSP1-specific B cells in Malian children and adults (ages 2 to 36 years), at well-defined time points before, during and after a febrile malaria episode. Our preliminary analysis shows that Pf-specific atypical MBCs display signs of activation after a febrile malaria infection. Using antigen probes to track influenza hemagglutinin-specific B cells in the same individuals, we have gained insight into the relative role of Pf in driving atypical MBC expansion and have also compared the magnitude and kinetics of Pf-and influenza-specific atypical and classical MBC responses. We further show that classical Pf-specific IgG+MBCs are activated and expanded, but interestingly, that a large proportion of activated Pf-specific MBCs are unswitched, expressing surface IgM. Additionally, we have single cell sorted Pf- and influenza-specific MBCs to compare their BCR features (VH gene diversity and somatic hypermutation rates). This analysis provides important new insights into the mechanisms underlying the inefficient acquisition of naturally acquired immunity to malaria in children.
The Role of Neutrophils in Pseudomonas aeruginosa Chronic Suppurative Otitis Media
Authors: Khomtchouk Kelly M , Kouhi Ali , Maria Peter Santa 
Published: January 2023

Abstract
Chronic suppurative otitis media is largely due to biofilm-forming bacteria, of which a common pathogen is Pseudomonas aeruginosa. Neutrophils are well-known to have various contributions in both promoting and restricting bacterial growth in other biofilm-mediated diseases, as they are one of the first cells recruited to sites of infection. Herein we propose that 1) fluorescent P. aeruginosa develop into biofilms and form chronic infections in the middle ear of a mouse model of Eustachian tube obstruction and acute tympanic membrane wounds; 2) this biofilm reduces functional capacity of professional phagocytes; 3) biofilm initiates apoptosis of responding neutrophils; and 4) neutrophils contribute to disease burden. We also determine neutrophil subsets with a leading role in the establishment of bacterial biofilm-mediated disease, and test the capacity of polymorphonuclear leukocytes to suppress planktonic infection.
Neutrophil function is quantified as a measure of phagocytosis and the production of extracellular traps; we also measure cell survival and clearance via efferocytosis to determine host-mediated barriers to this recalcitrant infection. Using flow cytometry coupled with fluorescent-tagged P. aeruginosa, we are able to assess middle ear effusion post-inoculation and develop a timeline of response to chronic infection in our novel CSOM model.
Importantly, this study establishes a model system for further immunological and translational studies, including testing of topical therapeutics. The results of this work will also inform potential efforts of neutrophils as predictors for disease exacerbation and guide additional therapeutic development for an illness affecting millions of children globally.
TcdB-specific plasma cell and memory B cell responses in recurring Clostridioides difficile infection-associated disease
Authors: Amani Souwelimatou Amadou , Shadid Tyler , Ballard Jimmy D , Lang Mark 
Published: January 2023

Abstract
Recurrence of C. difficile infection with progressively worsening disease is a serious problem. Serum IgG specific to the secreted toxin B (TcdB) is the best-known correlate of protection against disease symptoms and pathology. However, little is known as to whether and how infection stimulates protective humoral immunity. We hypothesized that recurring disease is due to an inadequate development of a TcdB-specific memory B cell response following an initial infection. We measured TcdB-specific antibody and memory B-cell responses following two sequential infections in microbiome-disrupted B6 mice. A mild infection caused by a low dose spore challenge did not induce an isotype-switched antibody response against the toxin and failed to protect against recurring disease. However, a higher-dose infection resulted in a TcdB-specific primary serum IgG1 and IgG2b response but did not boost titers. Also, in mice with TcdB-specific serum IgG1 there was a strong correlation with fecal TcdB-specific IgG1 and an attenuation of subsequent disease. Following infection of TcdB-immunized mice, IgG1 titers did not increase and ELISPOT analyses detected TcdB-specific IgG1-secreting plasma cells primarily in the bone marrow. Infection of pre-immunized mice also resulted in increased amounts of TcdB-specific IgG1 reaching the gut lumen. These findings indicate that a more severe initial encounter with the pathogen may be required to elicit a protective systemic TcdB-specific IgG1 response. Re-infection or infection of pre-immunized mice does not stimulate a B cell memory response and protection appears to be mediated by transport of plasma cell-derived systemic IgG1 to the gut lumen.
CD160-HVEM signaling in intestinal epithelial cells modulates gut microbial homeostasis
Authors: Seo Goo-Young , Shui Jr-Wen , Mikulski Zbigniew , Wang Qingyang , Takahashi Daisuke , Giles Daniel A , Iwaya Hitoshi , Sethi Ashu , Kim Pyeung-Hyeun , Cheroutre Hilde , Kronenberg Mitchell 
Published: January 2023

Abstract
Intestinal epithelial cells (IEC) are a first barrier that segregates host and commensal bacteria to maintain intestinal homeostasis. Intestinal intraepithelial lymphocytes (IEL) are located beneath or between adjacent IEC and directly contact IEC. The herpes virus entry mediator (HVEM), a member of the tumor necrosis factor receptor superfamily (TNFRSF), is highly expressed by IEC. Epithelial HVEM expression was previously reported as a regulator of innate immune defense during acute infections in the intestine (Shui et al., Nature, 2012). Here, we identify that HVEM signaling in IEC is important for the regulation of the gut microbiota at steady state. Mice with an epithelial-specific deletion of the gene encoding HVEM (HvemΔIEC) had significantly increased segmented filamentous bacteria (SFB) which caused an increase in Th17 cells in the ileum. Treatment with the antibiotic vancomycin eliminated SFB and decreased Th17 cells in HvemΔIEC mice. Additionally, mice with a deletion of the gene encoding CD160, which is a ligand for HVEM and is highly expressed by IEL, including intraepithelial innate lymphoid cells (ILC) and intraepithelial T cells, had increased SFB in the ileum. Our findings suggest that the interaction of CD160 expressed by IEL with HVEM expressed by IEC is important at steady state for shaping the microbiota in the intestine.
Zinc supplementation modulates T helper 17 cells via the gut microbiome
Authors: Gordon Sarah R , Vaishnava Shipra 
Published: January 2023

Abstract
Zinc is a dietary micronutrient that regulates various biological processes. Zinc is important for replication and survival of microbes and, as a result, a common strategy of the immune system is to steal zinc away from disease-causing microbes to prevent their growth. Recent studies show that changes in levels of dietary zinc can alter the composition of the gut microbiota, however how this impacts mucosal immune responses in the gut is not known. Here, we show that supplementing mice with zinc sulphate, a commonly used therapy for treating diarrheal episodes, in drinking water for a week resulted in significant changes in gut microbial composition as well drastic reduction in microbial diversity. More importantly. we saw that zinc supplementation attenuated the T helper17 cell number and activity in murine small intestine. To determine if zinc-dependent changes in gut microbiota are sufficient to limit Th17 response, we transplanted the microbiome from zinc treated mice into germ-free mice. We saw that germ-free mice that received cecal contents from zinc treated mice have reduced Th17 response, thus establishing that dietary zinc changes immune potential of the gut microbiome. Th17 cells mediate antimicrobial response in the gut and are involved in the pathogenesis of many autoimmune diseases. Our work thus provides a novel nutritional approach for remodeling microbiota to dampen inflammatory immune responses in the gut.
The adjuvant effects of MF59 on antigen-specific regulatory and effector T cells
Authors: Lin Pin-Hung , Yang Hung-Chih 
Published: January 2023

Abstract
Peptide vaccines are an ideal strategy to induce cross-protective T cell immunity against a broad range of influenza virus strains, but they are subimmunogenic and tend to induce regulatory T (Treg) cells. Our previous study has shown that adjuvanted peptide vaccines can suppress the development of antigen-specific Treg cells. MF59 is the first oil-in-water adjuvant approved for protein-based influenza vaccine, which enhances humoral and Th2 cellular immune responses. However, the role of MF59 in peptide-based vaccines regarding the induction of T cell immunity is unknown. We thus investigated the effects of MF59-adjuvanted peptide vaccines on antigen-specific T cell immunity against influenza virus infection. Using OT-I and OT-II TCR transgenic T cells, we found that the MF59-adjuvanted cognate OVA peptide vaccines induced a significant portion of OT-II Treg cells in primary immunization. However, MF59-adjuvanted peptide vaccine could prevent the expansion of pre-existing antigen-specific Treg cells. Of note, primary influenza virus infection induced a negligible portion of antigen-specific Treg cells, but secondary influenza virus infection drove the expansion of pre-existing Treg cells. Interestingly, swapping of the sequential immunizations with MF59-peptide vaccination and influenza virus infection resulted in very different levels of antigen-specific Treg cells, suggesting that the first immunization experience affects the development of antigen-specific Treg cells. Finally, MF59-peptide vaccines stimulated the production of IFN-γ and TNF-α of CD4 and CD8 T cells. In conclusion, MF59-peptide vaccine exhibits a unique feature in stimulation of antigen-specific T cell immunity.
Targeting antigen to lymph node lymphatic endothelial cells under steady-state to promote archiving and memory
Authors: Maulloo Chitavi D , Wilson David Scott , Hubbell Jeffrey A , Swartz Melody A 
Published: January 2023

Abstract
Lymphatic endothelial cells (LECs) have been shown to archive antigen (Ag), i.e. retain Ag in its native form, for weeks after exposure. We have developed a polymeric platform that promotes targeting of Ag to lymph node (LN)-resident LECs by exploiting the sugar-binding scavenger receptors expressed by LECs, leading to longer Ag retention over 2 weeks. This targeting results in enhanced Ag archiving in LECs, even in the absence of an adjuvant or other inflammatory stimuli previously shown to be necessary for Ag archiving in LECs. 2 weeks after subcutaneous (s.c.) delivery of unmodified OVA, we observed substantial proliferation and activation of adoptively transferred OVA-specific CD8+ T cells. Immunization and subsequent Ag archiving with our targeting polymer conjugated to OVA (without adjuvant) led to reduced CD8+ T cell proliferation but higher differentiation into a central memory phenotype, both by surface receptors as well as the ratio of EOMES vs. T-bet on activated T cells. We measured MHCI-mediated presentation of OVA (SIINFEKL presented on the H-2kb molecule) on LN-LECs vs. DCs over two weeks following s.c. injection and found that Ag presentation by LECs was comparable to DCs. This demonstrates that LECs are able to cross-present archived Ag directly to CD8+ T cells, with potential implications in the prolonged maintenance of memory CD8+ T cells and design of a more effective vaccine platform.