bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrinsic B cell TLR-BCR linked coengagement induces mature and protective antibody responses in the absence of T cells
Authors: Rivera Carlos Eduardo , Yan Hui , Fisher Amanda Dee , Chupp Daniel Phillip , Simon Raphael , Zan Hong , Xu Zhenming , Casali Paolo 
Published: January 2023

Abstract
Maturation of the antibody response is critical for the generation of virus and bacteria neutralizing antibodies. It entails CSR and SHM together with plasma cell and memory B cell differentiation, and it is generally dependent on T cell help. Prompted by our finding that CSR and plasma cell differentiation can be induced in vitro by a TLR ligand together with BCR crosslinking, we hypothesized that TLR-BCR coengagement can induce a fully mature antibody response in vivo in the absence of T cells, and such coengagement must entail physical linkage of TLR and BCR ligands. To test this hypothesis, we vaccinated Tcrβ−/− Tcrδ−/− mice with NP-LPS or Salmonella Typhimurium flagellin (coengaging B-cell TLR4 with NP-specific BCR or TLR5 with flagellin-specific BCR). Vaccination of Tcrβ−/− Tcrδ−/− mice with NP-LPS or flagellin induced activation of the B cell NF-κB pathway to elicit NP or flagellin-specific class-switched IgG and IgA antibodies and plasma cells. It also induced formation of germinal center-like (GC) structures, B cell SHM, selective clonal expansion and intraclonal diversification, and generation of memory B cells. Similar antibody responses to NP and flagellin were reproduced in NSG/B mice (by grafting immunodeficient NSG mice with purified C57BL/6 mouse B cells), thereby showing that such responses could be generated in the absence of not only T cells but all other immune cells. Finally, LPS and flagellin induced class-switched and specific antibodies which neutralized E. coli and S. Typhimurium, respectively, and protected mice from lethal infection. Thus, TLR-BCR coengagement can induce a mature and protective antibody response, complete with CSR/SHM, plasma cell and memory B cell differentiation in the absence of T cells.
Supported by NIH grants AI 079705, AI 105813/105813S1, AI138944, AI 167416 and Lupus Research Alliance grant LRA 641363 to Paolo Casali
Lactoferrin-derived Chimeric Peptide (LFch) boosts TGFβ1-induced Treg Differentiation by diminishing of TCR Signal intensity via TβRIII
Authors: Jang Young-Saeng , Yang Seok-Won , Park Sunhee , Kim Yu-Rim , Han Joo-Hee , Kim Pyeung-Hyeun 
Published: January 2023

Abstract
Regulatory T cells (Tregs) are a special subset of T cells to suppress excessive immune response and maintain immunologic tolerance. It is known that lesser TCR signal strength is favorable for Foxp3+ Treg differentiation. We recently reported that LF substantially promoted Foxp3 expression by activated CD4+ T cells and this activity was further enhanced by TGF-β1. In the present study, we explored the effect of lactoferrin chimera (LFch, synthetic LF-derived chimeric peptides) along with TGFβ1 on Foxp3+ Treg differentiation. LFch itself did not induce Foxp3 expression. However, LFch dramatically enhanced TGFβ1-induced Foxp3 expression. LFch little affected the phosphorylation of Smad3, which is a canonical TGF-β1 mediator. Instead, LFch decreased the phosphorylation of S6, IkB, and PI3 kinase (an activation hallmark of TCR signaling). These effects of LFch were completely abolished by pretreatment of LFch with soluble TβRIII. Consistently, the enhancement of TGFβ1-induced Foxp3 by LFch was also abrogated by treatment of soluble TβRIII. Finally, TGFβ1/LFch-induced T cell population substantially suppressed the proliferation of responder CD4+ T cells. These results indicate that LFch potently enhances TGFβ1-induced Foxp3+ Treg differentiation by diminishing TCR signal intensity through TβRIII.
CD6 – a costimulatory receptor at the nexus of Teff / Treg development
Authors: Ampudia Jeanette , Chu Dalena , Connelly Stephen , Ng Cherie 
Published: January 2023

Abstract
The balance of proinflammatory effector T cells (Teff) and anti-inflammatory regulatory T cells (Treg) is associated with autoimmune and inflammatory diseases. CD6 is a costimulatory receptor expressed on T cells with its greatest expression on pathogenic Teff cells, while Tregs are CD6low. Notably T cells from CD6knockout mice fail to differentiate to Th17 cells but were seen to skew to a Treg phenotype more rapidly. Although the role of CD6 in Teff development is well characterized, here we sought to investigate the role of CD6 in the development of Treg cells.
Itolizumab, a humanized anti-CD6 monoclonal antibody that modulates cell surface levels of CD6, was used to generate CD6low naïve T cells, after which itolizumab was removed and Tregs were differentiated using a standard protocol. Tregs derived from CD6low cells had greater co-expression of FOXP3 and HELIOS (~2-fold) vs. Tregs derived from isotype-treated CD6high. These Tregs possessed greater suppressive function, with increased inhibition of proliferation and cytokine release by stimulated T responder cells by at least 50% more than Tregs derived from CD6high cells; this was verified in three different donors. Similar observations were made when measuring levels of cytokines. CD6low Tregs were able to suppress T responder’s production of proinflammatory cytokines by 60–90% compared to CD6highTregs.
This is the first study to directly characterize the role of CD6 in the development and activity of Treg cells. These data suggest that reduced levels of cell surface CD6 facilitate the development of Treg cells with greater stability and suppressive activity and that modulating the levels of CD6 may decrease the Teff/Treg ratio in patients with autoimmune and inflammatory diseases.
A potential monocyte-regulatory T cell axis in neurorestoration following ischemic stroke
Authors: Rahimpour Shokofeh , Zheng Wen , Monaghan Kelly L , Wan Edwin C K 
Published: January 2023

Abstract
Neurorestoration following ischemic stroke is regulated by a complex interaction between the resident glial cells and the immune cells infiltrated to the brain. Using transient middle cerebral artery occlusion (tMCAO), it was shown that both monocytes and regulatory T cells (Tregs) play a critical role in facilitating neurorestoration following ischemic injury of the brain. However, the underlying mechanisms are not well-understood. Importantly, it is unclear whether the neurorestorative effect of monocytes and Tregs require their cognate interaction. The goal of this study is to investigate the interplay between monocytes and Tregs in facilitating brain recovery following ischemic injury. Using mouse tMCAO model, we found that 1) Monocytes were present in the brain both at the sub-acute (day 3) and chronic phases (day 14) following tMCAO, whereas Tregs were significantly increased in the brain only at the chronic phase. 2) During the chronic phase, monocytes and Tregs interacted within the glial scar. 3) CCR2, which controls monocyte trafficking, was expressed in monocytes but not in Tregs, but the number of both monocytes and Tregs were substantially reduced following tMCAO when CCR2 was deleted. 4) CCR2-deficient mice had a reduced survival rate and a larger area of glia scar during the chronic phase post-stroke compared to CCR2-sufficient mice. 5) Tregs in the cervical lymph nodes expressed CCR4 following tMCAO, which is known to control Treg trafficking. 6) Monocytes express CCR4 ligands, CCL17 and CCL22, during differentiation into monocyte-derived cells (MDCs) in vitro. Thus, our data demonstrate that monocytes may exert their neuroprotective via the regulation of Treg trafficking and/or expansion following ischemic stroke.
This work was supported by NIH grants P20GM109098 and R21NS125056 to Edwin Wan. Kelly Monaghan was supported through The American Association of Immunologists Careers in Immunology Fellowship Program.
Evaluation of the DNA topoisomerase inhibitor irinotecan (CPT-11) as an alternative to irradiation for pretreatment of NK-92s prior to adoptive cell immunotherapy.
Authors: Cruz Amaya Judith B , Navarrete-Galvan Lydia T , Lombardi Vincent C , Isom Matthew , Smith-Gagen Julie , Hudig Dorothy 
Published: January 2023

Abstract
Irradiation damages both proteins and DNA, which reduces the cytotoxicity of NK-92 cells as well as preventing their growth and engraftment when used for adoptive immunotherapies of cancer. We evaluated the DNA topoisomerase inhibitor irinotecan (CPT-11) as an alternative method to 10 Gy irradiation that might better preserve the perforin-granzyme cytotoxicity mediated by NK-92 cells towards tumor cells. Irinotecan is enzymatically converted into an active metabolite SN-38 which promotes its potential to become a delayed inhibitor in comparison to camptothecin which is a structurally similar topoisomerase inhibitor that is immediately active. We pretreated NK-92 cells for 4 hours with different concentrations of CPT-11, and measured NK-92 cell death and the effects on cell-mediated cytotoxicity towards Raji tumor cells (measured by 51Cr release one day after pretreatment). Previous experiments with 10 Gy irradiation were used for comparative purposes. Irinotecan had a dose response on cell death which progressed for 5 days. We found that one day after pretreatment with as little as 80 – 100 uM CPT-11, viable cell recoveries were similar to 10 Gy irradiated with over 50% compared to the counts of control cells. Activity of the viable cells after CPT-11 pretreatment, compared by lytic units, was over 30% conserved whereas irradiated cell activity was 2.9%, compared to controls. This data demonstrate that the negative effects of anti-proliferative treatment are less pronounced with irinotecan, than for irradiation. We conclude that optimization of dosage and exposure times to irinotecan may offer a means to prolong the life and function of NK-92 cells that are used for adoptive immunotherapies.
Supported by the Nevada INBRE NIH GM103440, for student summer research scholarship and the UNR Foundation C.E. Hudig Fund.
Structure of NAD+ consuming Acinetobacter baumannii TIR domain.
Authors: Snyder Greg A , Nallar Shreeram , Snyder Michelle , Krishanu Ray 
Published: January 2023

Abstract
Toll-like and Interleukin-1/18 receptor (TIR) resistance proteins have been identified across biology to function as important multimodal signal transduction and immune regulatory molecules. Select TIR domain containing proteins identified in both eukaryotic and prokaryotic species have also been found to have NAD+ hydrolase activity in bacteria, plants and in mammalian cells. We report the crystal structure of the Acinetobacter baumannii Toll-Interleukin-1 receptor resistance domain protein (AbTIR) determined to a resolution of 2.8 Å, confirm its enzymatic function in NAD+ hydrolysis and map its interaction with NAD+ using HDX-MS. Additionally, we have developed a novel assay for measuring AbTIR’s enzymatic activity in live bacteria using label-free quantitative two-photon fluorescence lifetime (FLT) imaging microscopy (2p-FLIM). These studies provide new insight into TIR protein mechanisms and their varying roles across biology.
Supported by R01 AI-082299, R21 CA191726-01
Host humoral immune suppression by Clostridioides difficile Toxin A and Toxin B
Authors: Ballard-Norman Kaylee M , Ballard Jimmy D , Lang Mark L 
Published: January 2023

Abstract
Gram-positive Clostridioides difficile is the greatest cause of nosocomial enteric disease in the US and is associated with a high rate of morbidity and mortality. During C. difficile infection (CDI), two secreted toxins (TcdA and TcdB) drive pathogenesis. Although T-dependent humoral immunity, specifically high affinity TcdA- and TcdB-neutralizing IgG, is the best correlation for protection against CDI recurrence, this response is commonly lacking following CDI in both mice and patients, leading to a high chance of recurrence. We previously showed that in murine CDI, there was a lack of T follicular helper (Tfh) cell differentiation, reduced IgG class-switching, poor toxin neutralization, and lack of resistance to reinfection. Preliminary data also suggested that TcdB inhibited IgG responses following vaccination against C. difficile. We therefore hypothesize that TcdA and/or TcdB suppress C. difficile-specific T-dependent humoral immunity. Following either CDI or intraperitoneal injection with TcdA or TcdB, immune cells from mesenteric lymph nodes were analyzed for changes in gene expression. Changes in dendritic cell maturation markers were observed in the presence of TcdB but not TcdA. Multi-targeting mRNA profiling showed altered expression of antigen presentation and CD4+ T cell activation genes. Only one of the known TcdB cell entry receptors was expressed by immune cells, specifically by CD4+ T cells and B cells. Efforts are underway to measure the impact of TcdA and TcdB treatment on CD4+ T cell differentiation, Tfh proliferation, and T-B cell interactions. Our data indicate that toxins may hamper neutralizing IgG production by affecting multiple aspects of T-dependent humoral immunity.
This work was supported by NIH grants AI134719 (M.L.L.) and AI119048 (J.D.B.).
Commensal Lactobacillus reuteri tryptophan catabolism promotes host susceptibility to CNS autoimmunity
Authors: Montgomery Theresa L , Eckstrom Korin M , Heney Eamonn R , Wargo Matthew J , Krementsov Dimitry N 
Published: January 2023

Abstract
Members of the Lactobacillus genus have a long-standing history in food processing and probiotic industries, generally being characterized as safe and/or beneficial for the mammalian host. Despite this fact, current literature points to pro- and anti-inflammatory roles, with little consensus as to the mechanisms governing these divergent outcomes. We and others have previously shown that commensal colonization with Lactobacillus reuteri (L. reuteri) enhances host susceptibility to experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis. To identify underlying mechanisms, we characterized the genome of commensal L. reuteri isolates, present within our model microbiomes, using whole genome sequencing and comparative genomics. The enzymatic machinery necessary to catabolize dietary tryptophan (Trp) into immunomodulatory indole derivatives, was enriched in the L. reuteri genome. Metabolite profiling of L. reuteri monocultures and serum of L. reuteri-colonized mice revealed active depletion of kynurenines and production of a wide array of Trp-derived AhR ligands, including indole acetate, indole acrylate, tryptamine, and imidazole derivatives, suggesting that Trp catabolism by L. reuteri may drive the enhancement of autoimmunity. Consistently, dietary Trp was required for L. reuteri dependent EAE exacerbation, while depletion of Trp suppressed disease activity and inflammatory T cell responses in the CNS. Our data suggests that Trp catabolism by gut commensals can enhance autoimmunity by production of immunoregulatory indole derivatives and by competition with the host for production of Trp metabolites such as kynurenines.
Supported by NIH R01 NS097596 T32 Training Grant 5T32AI055402-15 F31 Ruth L. Kirschstein NRSA Fellowship 5 F31 NS120381-02
Indispensable roles of TNF signals in protective immunity against Orientia tsutsugamushi infection
Authors: Liang Yuejin , Trent Brandon , Card Galen , Fisher James , Sun Jiaren , Soong Lynn 
Published: January 2023

Abstract
Scrub typhus is an emerging tropical disease caused by obligate intracellular bacteria Orientia tsutsugamushi, with over one million cases reported yearly. Patients may develop acute lung injury and multi-organ failure; the worldwide average mortality rate is 6%; however, little is known regarding key immune mediators during infection. Using murine scrub typhus models, we demonstrated the essential role of TNF signals in bacterial control and host protection. Mice lacking both TNF receptors (TNFR1/R2−/−) or receiving anti-TNF-α treatment were highly susceptible to infection with significantly increased tissue bacterial loads, inflammatory responses, and mortality. Their lung- and spleen-derived leukocytes displayed profound defects in total cell numbers and activation status for both innate immunity (NK cells, neutrophils, and macrophages) and adaptive immunity (CD4+ and CD8+ T cells). Infection of TNFR1−/− or TNFR2−/− mice confirmed the requirement of both receptors in efficient control of disease progression, as lacking either one receptor greatly reduced activated CD4+ and CD8+ T effector cells. Together, this study demonstrates a critical and indispensable role of TNF signals in host protective immunity against O. tsutsugamushi infection and severe scrub typhus.
Supported by grants from NIH (R01 AI132674, R21 AI156536 and R21 AI153586).
Early Life Development of Bronchial Associated Lymphoid Tissue Containing Germinal Center in the Human Lung
Authors: Matsumoto Rei , Gray Joshua I , Connors Thomas J , Guyer Rebecca , Rybkina Ksenia , Bradley Marissa , Poon Maya M L , Farber Donna L 
Published: January 2023

Abstract
Early life susceptibility to respiratory pathogens is well established in infants and young children, however the specific adaptations of the infant immune system for responding to multiple respiratory challenges are not known. Here, we examined lung and lung-associated lymph nodes derived from infant and pediatric organ donors (0–13 years) by confocal immunofluorescence and high dimensional flow cytometry. We identified early formation of bronchial associated lymphoid tissue (BALT) where active immune responses are initiated. At 8 days of life, few immune cells were present around the airways. By 5 months old, we start to observe BALT formation. However, BALT lose their structure with aging and are mostly absent by 10 years of age with CD4 memory T cells dominating the population around the central airways. Germinal centers are seen in 50–60% of BALT during the first two years of life. The percentage of BALT with germinal centers decreases over age, while germinal center formation in lung lymph nodes is maintained throughout infancy and childhood. Flow cytometry data shows seeding of transitional and immature B cells in the lung during infancy, which decreases over age. However, proportion of IgG and IgA memory B cells increases significantly over age both in the lung and lung lymph nodes. The frequency of naïve B cells is stable throughout childhood in both sites. Our results suggest that localized tertiary lymphoid structures in pediatric lungs may be an important mechanism for mobilizing rapid in situ protection during the first few years of life when memory T cells and B cells are not fully established.
Supported by grants listed below: “Human Atlas of Neonatal Development and Early Life-Immunity (HANDEL-I)”(award Number 2018PG-T1D071 The Leona M. and Harry B. Helmsley Charitable Trust) “Immunobiology and alveolar physiology of the aging lung” (U01 HL145547, NIH/NHLBI)
Diet induced changes in microbiota composition affect the development of small intestinal T cells over generations
Authors: Barragan Luisa Cervantes , Royer Charlotte , Yaceczko Maddelyn , Rodriguez-Marino Naomi 
Published: January 2023

Abstract
The relationship of microbiota and host is a dynamic and bidirectional process. The microbiota has a strong influence in the development of the host’s immune system, yet the host shapes the composition of the microbiota as well, through the immune response, and importantly, through diet. In the current study we evaluated how modification in the carbohydrate and fiber content of a diet impacts the intestinal immune response. Mice were weaned into a standard natural ingredient diet (Reg) or a purified non-fermentable fiber only diet (NFF) and the immune cell composition was analyzed after four weeks. Animals in the NFF diet had strong changes in their microbiota composition and defects in the development of small intestinal intraepithelial T cells including the lack of CD4+CD8aa+ T cells and TCRab+CD8ab+ T cells. The effect of NFF consumption both in microbiota composition as well as IEL T cell development, was reversible if animals were fed a Reg diet. However, if animals were born from parents fed an NFF diet and kept on NFF diet until weaning, the effect on IEL T cells was non reversible and the offspring of these mice did not develop IEL T cells even if fed a reg diet. Fecal matter transplant from mice fed a Reg diet, together with a Reg diet was able to induce the development of IEL T cells, suggesting the defect observed in the offspring of mice fed a NFF diet is the result of the loss of microbes required for the development of IEL T cells. This study shows how changes in the diet can result in the loss of specific microbiota species over generations that are important for the correct development of the intestinal immune system.
Supported by grant from NIH RO1 DK129950-01
Perturbed function of natural killer cells by inflammatory cytokines in acute (AML) and chronic (CML) myeloid leukemias
Authors: Kuznetsova Valeriya , Patel Sweta , Luca Francesca , Camacho Virginia , Matkins Victoria , Welner Robert S 
Published: January 2023

Abstract
Natural killer (NK) cells have the capacity to eliminate malignant cells by releasing cytotoxic granules. Indeed, mature NK cell counts are associated with favorable prognosis in AML and prolonged TKI-free remission in CML. However, NK cell maturation and anti-leukemic activity are suppressed during the disease, and the environmental drivers of this impairment remain unclear. Given an established role of inflammatory cytokines (particularly IL-1β, IL-6, and TNFα) in the progression of myeloid malignancies, we define their impact on NK cell function in chimeric mouse models of leukemia – Flt3-ITD/TET2, AML/ETO9a, Meis/Hox (AML), and BCR-ABL1 (CML), where NK cells do not carry the oncogene. Reflecting clinical observations, NK cell frequencies and numbers are reduced, implying oncogene-independent mechanisms of NK dysfunction in different leukemic subtypes. Moreover, both AML- and CML-exposed NK cells display immature phenotypes, diminished expression of activating receptors, and impaired ex vivo target-specific degranulation. The single cell RNA-seq analysis of CML-exposed NK cells confirmed decreased expression of NK maturation and cytotoxicity markers and upregulation of inhibitory receptors and genes associated with inflammatory cytokine response. Furthermore, IL-6-STAT3 and IL-1β/TNFα transcriptional signatures are enriched during the disease, which is likely to be triggered by leukemic cytokines. Thus, we next found that leukemic serum dampens NK cell degranulation ex vivo, compared to serum from control mice. These data suggest that soluble leukemic factors contribute to NK cell dysfunction and represent an optimal target for NK-boosting immunotherapies across different types of myeloid malignancies.