bluuebunny/crossref_metadata_2025_split huggingface dataset:
The microbiome and IL-10 are critical factors in regulating the number of marginal zone B cells (P1086)
Authors: Dittel Bonnie , Basu Sreemanti , Ray Avijit 
Published: January 2023

Abstract
Marginal zone (MZ) B cell positioning within the spleen allows them to rapidly respond to blood-borne pathogens. Very little is known regarding how MZ B cell homeostasis is controlled. We found a critical role for IL-10 and the microbiome in regulating MZ B cell numbers. Specifically, IL-10-/- mice obtained from Jackson Lab (JAX) but maintained in our colony exhibited a significant increase in the absolute number of MZ B cells. However, mice from JAX had normal numbers of MZ B cells. When we co-housed IL-10-/- JAX mice with our IL-10-/- mice, MZ B cell numbers were significantly increased. These results suggested that the microbiome plays a prominent role in regulating MZ B cell homeostasis. To confirm this, we treated IL-10-/- JAX mice with broad-spectrum antibiotics during the co-housing period and were able to prevent the increase in MZ B cell numbers. In addition, the treatment of our IL-10-/- mice with antibiotics was sufficient to reverse the increase in MZ B cells. One major difference between the two sources of mice is that ours are colonized with helicobacter, a contributing factor to inflammation and colitis. We found that specific colonization of JAX IL-10-/- mice with helicobacter was sufficient to increase MZ B cell numbers. Thus we have uncovered that IL-10 controls a regulatory loop whereby specific bacteria in the gut capable of inducing inflammation drive an increase in MZ B cells that would be beneficial should a breach in the gut result in sepsis.
Interleukin-21-induced granzyme B-expressing B lymphocytes regulate T cells and infiltrate tumors (P1088)
Authors: Lindner Stefanie , Dahlke Karen , Sontheimer Kai , Hagn Magdalena , Kaltenmeier Christof , Barth Thomas , Beyer Thamara , Reister Frank , Fabricius Dorit , Lotfi Ramin , Lunov Oleg , Nienhaus G. Ulrich , Simmet Thomas , Kreienberg Rolf , Möller Peter , Schrezenmeier Hubert , Jahrsdörfer Bernd 
Published: January 2023

Abstract
The role of B cells in tumor infiltrations is controversially discussed. Different studies suggest that certain tumor-infiltrating B cell populations exhibit regulatory potential. Here, we demonstrate that the microenvironment of various solid tumors contains granzyme B (GrB)-expressing B cells adjacent to IL-21-providing T cells. Since GrB-mediated effector T cell modulation is known from regulatory T cells (Treg) and plasmacytoid dendritic cells, we hypothesized the existence of similar mechanisms in B cells. Here we show that IL-21 induces B cells expressing high levels of GrB and controlling T cell proliferation by GrB-dependent degradation of the T cell receptor ζ-chain. Detailed characterization of IL-21-induced GrB+ B cells reveals a CD19+CD38+CD1d+IgM+CD147+ phenotype and expression of additional regulatory molecules including IL-10, CD25 and IDO. Of note, IL-21-mediated GrB induction integrates both BCR- and TLR-mediated signals and is enhanced in the presence of B cell CD5 expression. This is the first report demonstrating that IL-21 induces GrB+ human regulatory B cells, which can be detected in tumor infiltrations, and which may contribute to the modulation of cellular adaptive immune responses by Treg-like mechanisms. Our findings may stimulate the development of novel diagnostic and cell therapeutic approaches to the management of malignant, autoimmune and graft-versus-host pathologies.
Effects of LPS on NF-κB p65 and anti-inflammatory cytokines mRNA expression in MSC (P1096)
Authors: Gang Wang , Haiyan Wang , Hong Liang 
Published: January 2023

Abstract
Abstract Objective To investigation the effects of Inflammatory simulated by LPS on mRNA expression of NF-κB p65, anti-inflammatory cytokines (IL-10, TGF-β3) and IDO in rat bone-marrow MSC. Methods The MSC cultured in vitro was divided into 6 groups: The normal group, the PDTC(100μmol/L) treatment group, the PDTC(100μmol/L)plus LPS(5µg/mL) treatment group and the 3 LPS dose (1, 5, 10μg/mL) treatment groups. After LPS supplement for 4 hr, the total RNA of the MSC was extracted and the mRNA expression of p65, IL-10, TGF-β3 and IDO were detected by RT-PCR. The gray scale was used to compare the mean levels (X±S) of PCR product within groups were determined. Results Compared with the control group, the mRNA expression of NF-κB Subunit p65 and anti-inflammatory cytokines IL-10, TGF-β3 were significant increased in the LPS treated groups (P &lt;0.05). The correlation coefficient between p65 and IL-10, TGF-β3 were 0.844(P&lt;0.05), 0.837(P&lt;0.05) respectively. The correlation coefficient of p65 with IDO was -0.942 (P&lt;0.05). Conclusion 1 LPS stimulation could induce MSC produce more anti-inflammatory cytokines through the activation of NF-κB. 2 IDO was constitutively expressed in normal cultured MSC, and its expression may be down regulated by inflammatory stimulation. This result indicates that there are different immune-modulation pathways in MSC under different microenvironments. Key words MSC; NF-κB; IL-10; TGF β3; IDO
Complement protein C1q influences macrophage-mediated T cell activation (P1062)
Authors: Clarke Elizabeth , Weist Brian , Walsh Craig , Tenner Andrea 
Published: January 2023

Abstract
Complement protein C1q opsonizes apoptotic cells (AC) to enhance ingestion by human monocyte-derived macrophages (Mϕ) before membrane integrity of the dying cell is lost, thus avoiding the release of inflammatory DAMPS and/or autoantigens. Additionally, Mϕ ingesting C1q-bound autologous AC (C1q-polarized Mϕ) produce enhanced anti-inflammatory and reduced pro-inflammatory cytokines. To understand the functional consequences of C1q interaction with Mϕ, we evaluated the induction of PD-L1 and PD-L2, molecules that bind T cell PD-1 resulting in inhibition of T cell activation, and the effect of C1q-polarized Mϕ on the T cell response to antigen stimulation. First, C1q-polarized Mϕ significantly upregulated both PD-L1 and PD-L2. Second, co-culture of C1q-polarized Mϕ with allogeneic T cells in a mixed-leukocyte reaction (MLR) for 3, 5 or 6 days did not modulate overall T cell proliferation relative to Mϕ ingesting AC alone, but decreased CD4+ T cell proliferation at day 3 (n=3) and increased Foxp3+ T cell proliferation at day 5 (n=4) relative to Mϕ ingesting AC alone. These data suggest that C1q-polarized Mϕ can influence T cell activation. C1q deficiency results in systemic lupus erythematosus (SLE) with &gt;90% penetrance, but the molecular mechanisms involved have not yet been determined. Further investigation of C1q-mediated effects on T cell proliferation could lead to the identification of novel target pathways for therapeutic intervention in SLE and other autoimmune diseases.
Regulated expression of anti-apoptotic MCL-1 and A1 controls the population structure of myeloid derived suppressor cells (P1070)
Authors: Haverkamp Jessica , Bronte Vincenzo , Herold Marco , Opferman Joseph , Murray Peter 
Published: January 2023

Abstract
Myeloid-derived suppressor cells (MDSCs) are an immunosuppressive population of immature monocytic and granulocytic cells. MDSCs emerge from the bone marrow as inactive precursors and upon migration to sites of inflammation become activated regulatory cells. However, both the fate and key immunosuppressive subsets within the MDSC pool at inflammatory sites remain unclear. Here we show MDSCs express high amounts of anti-apoptotic MCL-1 and A1. We reasoned if MCL-1 was ablated in MDSC populations, MDSCs would be less suppressive and more prone to apoptotic death. However, MCL-1 deficient MDSCs were more suppressive than wild type (WT) MDSCs because MCL-1 deficient MDSCs were predominately monocytic in lineage. In the absence of MCL-1, granulocytic MDSCs are apoptotic and are not functional suppressor cells. These data define monocytic MDSCs as the key immunosuppressive population. When we sorted purified monocytic MDSCs from MCL-1 deficient mice we found they had reduced suppressive activity and higher apoptosis than sorted WT monocytic MDSCs. Further investigation demonstrated in the absence of MCL-1, regulated A1 expression in monocytic MDSCs is necessary for their full suppressive capacity and survival. Furthermore, we show GM-CSF is a key player in the survival of monocytic MDSCs via A1 regulation. These data have implications for the engineering of MDSCs as suppressors for autoimmune diseases and therapies to selectively ablate monocytic MDSCs in the treatment of cancer.
Altered host immune responses, not lowered growth, are the mechanism of attenuation of Francisella tularensis clpB (P3126)
Authors: Barrigan Lydia , Tuladhar Shraddha , Brunton Jason , Woolard Matthew , Chen Ching-ju , Saini Divey , Frothingham Richard , Sempowski Gregory , Kawula Thomas , Frelinger Jeffrey 
Published: January 2023

Abstract
Bacterial infections typically initiate both innate and adaptive immune responses. Bacterial attenuation is thought of as altered bacterial growth in the presence of constant immune pressure. In vivo screens have identified F. tularensis genes necessary for virulence. While many of these mutations render F. tularensis incapable of intracellular growth, some mutations have no impact on intracellular growth. We hypothesize that these F. tularensis mutants are attenuated because they induce an altered host immune response. We were particularly interested in the F. tularensis LVS mutant clpB (FTL_0094). Our LVS clpB strain is attenuated in pneumonic tularemia yet we did not observe an intracellular growth defect in bone marrow derived macrophages. We showed that LVS clpB induced an altered innate, but equivalent adaptive, immune response compared to LVS. In B6 mice, LVS clpB induced pro-inflammatory cytokine production in the lung early after infection in contrast to wild-type LVS infection. LVS clpB provoked a robust protective adaptive immune response similar in magnitude to LVS, but with increased IFN-γ and IL-17A production in the lung as measured by mean fluorescence intensity. Altogether, our results indicate that LVS clpB is attenuated due to altered host immunity and not an intrinsic growth defect. These results also indicate that disruption of non-essential gene(s) that cause attenuation, like F. tularensis clpB, can help elucidate bacterial immune evasion mechanisms.
Persistence of antibodies targeting B cell epitopes of Plasmodium falciparum VAR2CSA (P3114)
Authors: Babakhanyan Anna , Leke Rose , Fowkes Freya , Taylor Diane 
Published: January 2023

Abstract
P. falciparum infection poses a major health risk for 85 million women during pregnancy, due to placental pathology resulting from the binding of malaria-infected erythrocytes to trophoblasts via the pregnancy-specific parasite adhesin VAR2CSA. We have demonstrated a correlation between high avidity antibodies (Ab) to VAR2CSA and protection from placental malaria. Ab to most malarial adhesins appear to be short lived, requiring exposure to antigen to sustain serum IgG. In the current study, we used serum collected longitudinally from pregnant Cameroonian women receiving antimalarial prophylaxis to help establish the half-life of Ab to VAR2CSA. VAR2CSA IgG levels were determined using a bead-based multianalyte platform. The half-life of IgG to VAR2CSA (5yr) was short compared to that found in pregnant Thai women (142 yr) and for viruses (ex. measles: 457 yr), but longer than for other non-pregnancy associated malarial antigens (ex. MSP-1: 2yr). Differences in IgG half-life between the two sites could be due to differences in malaria transmission: seasonal in Thailand, but year around in Africa. In Africa, frequent exposure to VAR2CSA during pregnancy may cause prolonged antigenic stimulation leading to continuous B cell activation with formation of short-lived plasmablasts and not long-lived B cells. Knowing how long IgG to VAR2CSA persists is important for establishing continuous protective immunity against malaria in pregnant women.
Mechanisms of inhibition of CD8+ T cell immunity during helminth infection (P3051)
Authors: Marple Andrew , Wu Wenhui , Grotenbreg Gijsbert , Gause William , Yap George 
Published: January 2023

Abstract
Upon infection, the protozoan parasite Toxoplasma gondii induces a strongly polarized Th1 cytokine response, necessary for effector differentiation of CD8 lymphocytes. Pre-infection with an intestinal nematode, such as Heligmosomoides polygyrus has been shown to attenuate immune responses to intracellular pathogens and inhibit the development of Th1 responses. Previous studies have shown that mice co-infected with H. polygyrus and T. gondii exhibit suppressed CD8+ T cell responses against T. gondii, yet the precise mechanism by which co-infection impinges upon the priming and differentiation of antigen-specific T cells remains to be determined. Using a novel Kb-peptide tetramer-binding assay for tgd057-reactive CD8+ T cells, we show that co-infected mice develop a diminished antigen-specific response to T. gondii. Co-infected mice developed fewer antigen-specific CD8+ T cells, a decreased fraction of terminally differentiated effector cells, and reduced effector IFN-γ production. Terminally differentiated antigen-specific effector T cells (CD62Llo, KLRG1+) from co-infected mice retained an intrinsic defect in cytokine production, which is associated with the expression of Spry2, an inhibitor of receptor tyrosine kinase signaling. While tgd057-specific CD8 differentiation and effector function remained inhibited in co-infected STAT6-/- and IL-10-/- mice, helminth-induced inhibition of differentiation and effector function was abrogated in co-infected IL-4/IL-10-/- mice.
Programmed death ligand 2 is a regulator of proinflammatory Th17 responses and immunopathology in murine infection with Schistosoma mansoni (P3085)
Authors: Salantes Danielle , Larkin Bridget , Ponichtera Holly , Sharpe Arlene , Stadecker Miguel 
Published: January 2023

Abstract
Schistosomiasis is a CD4 T cell-mediated inflammatory disease caused by parasitic helminths of the genus schistosoma. The main cause of morbidity and mortality in both humans and an experimental mouse model are tissue-lodged parasite eggs. For reasons not yet fully understood, the severity of immunopathology varies widely amongst mouse strains: CBA/J develop severe disease with an elevated Th17 response whereas C57BL/6 develop mild pathology with a Th2-polarized response. In view of several studies showing that Programmed Death-1 and its ligands PD-L1 and PD-L2 suppress a variety of T cell-mediated immune responses, we hypothesized that this co-inhibitory pathway downregulates the granulomatous response to schistosome eggs, thus preventing severe pathology. We now show that infection in BL/6 mice results in a larger population of PD-L2+ CD11c(hi) splenocytes than in CBA mice. Moreover, PD-L2 deficient BL/6 mice display markedly exacerbated hepatic granulomatous inflammation together with a significant increase in Th17 cells, whereas in PD-L1 deficient BL/6 mice these parameters are not significantly different from WT controls. These results suggest that the induction of PD-L2 expression represents a powerful means to control excessive T cell-mediated immunopathology in this major parasitic disease.
A role for B and T lymphocyte attenuator in regulating T cell responses during Tuberculosis (P3088)
Authors: Grover Ajay , Troudt Jolynn , Foster Chad , May Nick , Izzo Angelo 
Published: January 2023

Abstract
B and T lymphocyte attenuator (BTLA) (CD272) is a coinhibitory receptor expressed by most leukocytes, with the highest expression levels observed on T and B cells, and is involved in the maintenance of peripheral tolerance by dampening the activation of lymphocytes. We wanted to determine if BTLA signaling played a role in T cell meditated regulation during tuberculosis infection. The expression of BTLA was examined on activated (CD44hiCD62Llo) CD4+ T cells in lungs, spleen and lymph nodes in mice during pulmonary Mycobacterium tuberculosis infection. The expression of BTLA on activated CD4+ T cells increased at day 10 post-infection in lungs, when compared to naïve mice, but then declined at day 21 post-infection. In the spleen and lymph nodes while the number of cells expressing BTLA increased, the expression of BTLA on these cells did not increase. Although the number of CD4+BTLA+ T cells in the lungs had increased at day 21, these cells expressed lower levels of BTLA than at day 10, suggesting that BTLA expression was down-regulated during this time. We also found an increase in the percentage of activated and effector memory T cells in the organs when BTLA was blocked using an anti-BTLA antibody during early stage of tuberculosis infection. Further, increased bacterial load was observed in the lungs of mice treated with anti-BTLA antibody indicating that BTLA regulates T cell-driven exacerbation of infection during the early stages of tuberculosis.
Perforin expression is required for fatal blood-brain barrier disruption in the Plasmodium berghei ANKA model of cerebral malaria (P3061)
Authors: Johnson Aaron , Johnson Holly , Huggins Matthew , N'Songo Aurelie , Hanson Lisa , LaFrance Stephanie , Jin Fang , Pirko Istvan , Butler Noah , Harty John 
Published: January 2023

Abstract
The most severe clinical complication of Plasmodium falciparum infection is cerebral malaria (CM). Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice is an established model of CM. Previous work has implied a role for CD8 T cells and perforin expression in fatal stages of PbA infection. We therefore infected C57BL/6 and C57BL/6 Perforin-/- mice with PbA and assessed the CNS for cerebral endothelial cell blood-brain barrier (BBB) disruption using FITC albumin leakage into tissue, confocal microscopy and 3D volumetric T2 and T1 gadolinium enhanced MRI. PbA infected C57BL/6 mice: 1.) had extensive disruption of BBB tight junction proteins Occludin and Claudin 5, 2.) developed severe CNS vascular permeability of FITC albumin and gadolinium leakage, and 3.) became moribund. We also observed increased VEGF cytokine expression coinciding with CNS vascular permeability in these animals. Despite having similar CD8 T cell infiltration into the brain, PbA infected C57BL/6 Perforin-/- mice had intact BBB tight junction, were devoid of CNS vascular permeability, presented with normal brain MRI, and had normal behavioral scores on the rotarod assay. This study is therefore the first to demonstrate the critical importance of perforin expression in promoting BBB tight junction alteration during PbA infection. Therefore, development of therapies to block factors related perforin mediated delivery could have significant benefit to the treatment of CM.
Myeloid cell-specific TRAF3-deficient mice exhibit normal myeloid cell development and homeostasis (P1196)
Authors: Lalani Almin , Moore Carissa , Liu Yan , Gerges Jocelyn , Xie Ping 
Published: January 2023

Abstract
Myeloid cells, including monocytes, macrophages and granulocytes, are crucial players of innate immunity and inflammation. These cells constitutively or inducibly express a number of receptors of the TNF receptor superfamily and Toll-like receptors (TLRs), whose signals are transduced by TRAF molecules. In light of the in vitro evidence that TRAF3 is required for TLRs-induced type I interferon production and for CD40-induced IL-12 production in macrophages, we generated myeloid cell-specific TRAF3-/- (M-TRAF3-/-; TRAF3flox/floxLysM+/Cre) mice to investigate the in vivo functions of TRAF3 in myeloid cells. We examined immune cell populations in the bone marrow, spleen, and peritoneal cavity in M-TRAF3-/- mice at the age of 8-12 weeks. No significant differences in the frequencies or numbers of immune cell populations such as B cells, T cells, granulocytes and macrophages were found between M-TRAF3-/- and littermate control (LMC) mice. TRAF3-/- macrophages also expressed similar levels of MHC class II, CD80 and CD86 as compared to LMC macrophages, suggesting that no endogenous activation of macrophages occurs. Our findings indicate that specific ablation of TRAF3 in myeloid cells neither affected myeloid cell maturation nor changed the homeostasis of macrophages and neutrophils. In contrast, activation of macrophages induced by TLRs was altered in the absence of TRAF3. Our ongoing study will further elucidate the in vivo functions of TRAF3 in innate immunity and inflammation.
Signal control of iNKT development and effector lineage differentiation (P1208)
Authors: Zhong Xiaoping , Wu Jinhong , Wang Shang , Shin Jinwook 
Published: January 2023

Abstract
The type I or invariant NKT iNKT) cells are among the first responders in various infectious and inflammatory settings and bridge innate and adaptive immunity. iNKT cells quickly producing numerous cytokines such as IFNγ, IL-17, IL-4, IL-13, and IL-10 to regulates innate and adaptive immune responses. iNKT cells contribute to the pathogenesis of allergy and asthma, autoimmune diseases, graft-versus-host disease, infections, cancer, and obesity as well as other diseases. While it is well established that the iVα14 T cell receptor and IL-15 receptor and numerous transcription factors are critically involved in iNKT cell development and effector lineage differentiation, the signaling events bridging the receptors and the transcription factors are poorly understood. We have recently demonstrated that diacylglycerol kinases α and ζ play crucial roles in iNKT cell development and that DGKα and ζ negatively control not only the well-known Ras-Erk1/2 and PKCθ-IKK-NFκB pathways but also mTOR signaling in T cells. We now reveal that mTOR signaling and its tight regulation play crucial roles in iNKT cells as deficiency of either mTOR or its regulator TSC1 profoundly impacts iNKT cell development and effector lineage differentiation.
Comparative analysis of different influenza virus strains (H1N1) in the pathogenesis and immune cell infiltration in the lungs in a mouse model. (P6192)
Authors: Kumar Sandeep , Biswas Moanaro , Deventhiran Jagadeeswaran , Elankumaran Subbiah 
Published: January 2023

Abstract
Influenza viruses cause annual seasonal epidemics around the world. Influenza pandemics of varied severity have been reported over time, among which, the 1918 pandemic was most severe. In the present study we sought to explore the pathogenesis and the infiltration of key immune cells in the murine lung following infection with A/PR/08/1934 (mouse adapted seasonal), A/New Jersey/11/1976 (localized epidemics) and A/Ca/04/2009 (pandemic) influenza viruses. We also sought to examine the role of hemmaglutinin (HA) glycoprotein of epidemic and pandemic influenza virus and of a single nucleotide mutation (D222G) in HA gene in altering disease pathology in infected animals. Animals were infected intra-nasally and scored daily for clinical signs (lethargy, ruffled fur and loss in body weight) for fifteen days. Pandemic virus infected mice were first to show clinical signs, though animals recovered soon. Clinical signs were observed after 48hrs post infection in animals infected with mouse adapted seasonal influenza but these animals failed to recover and 100% mortality was observed on day 5-post infection. No clinical signs were observed in animals infected with epidemic influenza virus strain. Lung samples were collected from infected animals on days 1, 3 and 5-post infection and were analyzed for virus titers, immune cells infiltration, pro-inflammatory cytokines and histopathology. Results of these analyses will be discussed.