bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clean-up on IL-7 (P6290)
Authors: Martin Christopher , Surh Charles 
Published: January 2023

Abstract
IL-7 availability determines the size and character of the resting T cell pool and therapeutic intervention to manipulate IL-7 levels represents a point at which to control T cell numbers and naïveté. However, the mechanisms that naturally regulate IL-7 abundance remain ill-defined. Using novel mouse models and the IL-7-specific proliferative response of wild type T cells as a direct measure of the IL-7 available to T cells in vivo, we demonstrate that radioresistant cells are the peripheral source of IL-7 for both CD4+ and CD8+ mature T cells. Hematopoietic lineage cells, although apparently unimportant as a source of IL-7, are primarily responsible for limiting IL-7 availability through their expression of IL-7R. The results of this study are the first to directly test and support the consumption model of IL-7 homeostasis wherein the IL-7 that is constitutively produced by stromal cells is maintained in limited supply via receptor-mediated degradation by hematopoietic cells. Collectively, these data illuminate a formidable IL-7 cytokine sink that exists in vivo and inform the design of next-generation IL-7 therapies.
Mesenchymal stem cell effect on lymphocyte apoptosis is partially contact dependent. (P1056)
Authors: Marti Luciana , Normanton Marilia , Ribeiro Andreza , Kondo Andrea , Hamerschlak Nelson , Rizzo Luiz Vicente , Marti Luciana 
Published: January 2023

Abstract
Although a vast evolution in mesenchymal stem cell (MSCs) knowledge and their immunomodulatory properties, still unexplored fields, such as, its effect on T cell death. This study objective was to evaluate MSCs effect on PHA activated lymphocyte (CD3+) apoptosis in vitro. CD3+ co-cultivated with MSC presented less early apoptosis (EA) and late apoptosis/necrosis (LN) determined by Annexin V and Annexin V/Propidium Iodide co-expression, compared to the ones without MSC. After 48hs of MSC co-cultivation CD3+ EA mean was lower (9.1+2.8) then without MSC (12.7+2.0), the same was observed for LN that was lower (28.0+13) then without MSC (41.9+13) p&lt;0.05. To assess if this effect on lymphocytes were contact dependent, the co-cultivation was performed with or without 0.2µm transwell, and we observed that is partially contact, dependent since the CD3+ EA mean after 72hs of MSC co-cultivation (25.0+3.3) was lower than with transwell (32.7+4.0), but both were inferior than without MSC (45.0+7.3). Next, to evaluate cell type specificity, lymphocytes were co-cultivated with MSC, fibroblast and HUVEC. CD3+ cells presented less EA when co-cultured with MSC and fibroblast then with HUVEC. After 72hs of lymphocytes co-cultivation with MSC (n=4) (29.95+0.29) and fibroblast (30.70+1.62) EA were significant lower compared to HUVEC (38.85+1.33) p&lt;0.05. These results have shown that the MSC effect on CD3+ is partially contact dependent, and similar for MSCs and fibroblast, but not for HUVEC.
Antigen choice determines vaccine-induced generation of immunogenic versus tolerogenic DC (P1104)
Authors: Farkas Adam , Finn Olivera 
Published: January 2023

Abstract
A peptide derived from the tumor-associated antigen MUC1 (MUC1p) is seen as “self” by the immune system of MUC1.Tg mice. TCR.Tg CD4+ T cells specific for MUC1p proliferate less in MUC1.Tg mice relative to WT after vaccination with DC loaded with MUC1p. We hypothesized this hyporesponsiveness acted to prevent autoimmunity, and investigated the phenotype of post-immunization (i.v.) splenic DC as likely mediators of this tolerance to self. At 24 hours these DC primed naïve CD4+ T cells into Foxp3+ Treg versus IFNy+ T cells. Immunized MUC1.Tg mice also had fewer splenic DC compared to WT. This was due to a concurrent defect, relative to DC from immunized WT mice, in DC-produced myeloid cell-recruiting chemokines such as MIP-1a/b, RANTES, and CCL2. These DC were also less inflammatory as measured by lower IL-6, TNF-a and IL-1a and increased IL-10 production. Splenic DC were also phenotypically immature (CCR2+ MHCIIlo CD40lo CD86lo) and exhibited impaired motility ex vivo that was mechanistically linked to decreased NFkB pathway activation versus WT. The repressor of DC activation Zbtb46 was increased in DC exposed to “self’ antigen and these DC expressed more Aldh1/2 suggesting a novel role for retinoic acid-mediated tolerance in the spleen. Immunization of RIP.OVA mice with OVA gave similar results suggesting a general mechanism not unique to MUC1p as an antigen. Lastly, MUC1-specific Treg induced this tolerogenic DC phenotype, the mechanism by which we are investigating.
LRRK2 affects cytokine production and Ig secretion in activated B cells (P1060)
Authors: Chen Yi-Chun , Monroe John 
Published: January 2023

Abstract
Leucine-rich repeat kinase 2 (LRRK2), a 286 KDa multi-domain protein, is strongly associated with familial Parkinson disease, Crone’s disease, as well as Lupus in GWAS studies. However, the pathogenic mechanisms of LRRK2 are still unclear. In order to further study its functions, we developed a strain of GFP knockin knockout (KIKO) mice that replaced the exon2 of lrrk2 gene with gfp and eliminated endogenous LRRK2. Since it is highly expressed in different immune cells, especially B cells, we first determined that LRRK2 mainly expressed in T2, follicular, and marginal zone B cells, but not in pro-, pre-, immature, T1 or B1 B cells. After B cell activation by LPS or anti-IgM/ anti-CD40, there was no difference in proliferation as well as apoptosis between Wt and KIKO B cells. However, Wt and KIKO B cells showed statistically significant differences in cytokine production profiles. Re-stimulation of activated B cells by PMA and ionomycin showed KIKO B cells has differential cytokine productions. Meanwhile, activated KIKO B cells also showed impaired IgA and IgG3 secretion, though the Ig switching was normal. These indicate that LRRK2 may have a role in B cell effector functions, and further investigation is needed.
Myeloid cells regulate plasma cell responses in the lymph node (P1066)
Authors: Fooksman David , Nussenzweig Michel , Dustin Michael 
Published: January 2023

Abstract
Differentiation and survival of plasma cells requires the coordinated signaling from many different cell types, and these requirements vary depending on the tissue. In the lymph node, differentiating plasma cells migrate to the medullary cords where they can either arrest or exit the lymph node. Previously, we imaged and characterized plasmablast migration by intravital microscopy in the lymph node by transferring B cells expressing a YFP plasma cell reporter. Using recipient mice that express GFP in myelomonocytic cells, we observed that plasmablasts migrated along these cells in the medullary cords and arrested in contact with them. Since several cell types express GFP in this strain, we used a various ablation techniques to narrow down which subsets were engaged with plasmablasts and determine what role they perform. Ablation of one subset increased plasmablast numbers by 3 fold. This increase was largely due enhanced cell proliferation, but plasmablast apoptosis was also reduced. We have evidence to suggest that cytokine signaling and adhesion molecules play important roles. Localization of plasma cells in the lymph nodes may play an important function in controlling infection locally during early stages, while under autoimmune conditions, excessive plasma cell recruitment and survival can be detrimental. Regulating plasma cell survival and localization may provide ways to manipulating the immune response in both contexts.
Regulation of FcϵRI-mediated signaling and mast cell activation by adaptor protein Tespa1 (P1068)
Authors: Lu Linrong 
Published: January 2023

Abstract
Tespa1 (thymocyte-expressed, positive selection-associated 1) is a newly identified adaptor protein that is expressed in T cells, B cells and mast cells. Our previous study revealed its critical role in mediating TCR signaling and thymocyte positive selection. Tespa1-deficient mice have fewer mature CD4+ and CD8+ SP cells in thymus, reflecting the impairment of T cell development in these mice. We further revealed that Tespa1 interacts with Lat signolosome components Grb2 and PLC-γ1 and is essential for the assembly of this signolosome and mediating of downstream signals. Tespa1 is also highly expressed in Mast cells. Here we further explored the role of Tespa1 in Mast cell activation. We found that disruption of Tespa1 causes mast cells to be hyperresponsive upon the stimulation of FceRI receptor, evidenced by enhanced degranulation, cytokine production, and their ability to mediate anaphylaxis. We also found that more Grb2 and PLC-γ1 were recruited to the LAT1 signolosome rather than LAT2 signolosome, suggesting Tespa1 might regulate the balance of LAT1 and LAT2 signolosome assembly and downstream distal signaling transduction in mast cells.
Regulation of inflammatory diseases by cestode antigens: multiple receptors and a possible common pathway (P3128)
Authors: Terrazas Luis I. , Terrazas Cesar A. , Ledesma-Soto Yadira , Callejas Blanca , Espinoza-Jimenez Arlett , Bonifaz Laura , Satoskar Abhay R. 
Published: January 2023

Abstract
Helminth parasites bias the immune response toward Th2 and/or to a regulatory environment associated with high levels of IL-4, IL-13, IL-5 and IL-10. In addition, helminth infections impair immunity against other unrelated infections. Thus, helminths can modulate the immune response in their host, and they have multiple ways to escape or modulate the immune system. One of their potential evasion strategies involves modulating the early response of macrophages and dendritic cells (DCs). These modulatory activities have been exploited to interferer development of pro-inflammatory-mediated diseases such as arthritis (AR), type 1 diabetes (T1D), experimental autoimmune encephalomyelitis (EAE) and colitis. Here we show that Taenia crassiceps, a cestode, is able to ameliorate the severity of EAE, T1D and colitis, but not AR, mainly by down-regulating IL-12, TNF-a, IL-15, IL-17, IL-1b and NO production. However, as most of the effects of helminth infections in these kinds of diseases, the mechanisms involved remain mainly unknown. Using T. crassiceps antigens we reproduced the effects of the infection. Such antigens are rich in glycoproteins that appear to be binding by multiple receptors, including MGL, MR, and TLR2, and interfered with the inflammatory-induced NFκB p65 and p38 MAPK pathways. Interestingly, blockade of just one intracellular signaling pathway was enough to avoid the effect of T. crassiceps antigens on modulating DCs and programing Th2 responses.
Temporal co-option of host cell trafficking by Yersinia pestis during bubonic plague. (P3140)
Authors: Ang Wei Xin Gladys , St. John Ashley , Kunder Christian , Chan Elizabeth , Gunn Michael , Abraham Soman 
Published: January 2023

Abstract
Bubonic plague, caused by the gram-negative bacteria Yersinia pestis, is characterized by pathologically swollen lymph nodes (LNs) or buboes. The mechanism by which these buboes form and the adaptive function they provide for the pathogen, if any, remains unknown. We hypothesize that bubo formation is a strategy for flea-borne Y. pestis to establish a foothold in the host for subsequent systemic infection. Our studies indicate that colonization of the draining lymph node (DLN) from the site of infection occurs through the trafficking of infected dendritic cells and monocytes in temporally distinct waves. This is effected by redundant chemotactic signals, including through the receptors CCR7 and CCR2, as evidenced by the upregulation of multiple chemoattractants in the DLN during Y. pestis infection and the improved survival of infected CCR7KO and CCR2KO mice compared to wild-type.
Identification of factors required for intracellular survival of Pseudomonas aeruginosa (P3146)
Authors: Penaranda Cristina , Hung Deborah 
Published: January 2023

Abstract
Antibiotic resistance is becoming a greater threat to combating bacterial infections. Pathways directly responsible for infection, such as those involved in virulence or immune evasion, are likely to be good targets for novel approaches to treating infection; however, these approaches are currently not being pursued due to the lack of understanding of the requirements for bacterial survival within the host. Pseudomonas aeruginosa (PsA) is one of the most virulent opportunistic human pathogens and is often highly resistant to antibiotic therapy. Although it is traditionally considered an extracellular pathogen, PsA has been shown to invade and survive inside host cells. We hypothesize that this ability to survive intracellularly allows bacteria to become antibiotic insensitive, leading to the formation of reservoirs for recurrent infections. We have developed an in vitro infection model where we have identified genes required for intracellular survival in epithelial cells. We have also found strain specificity among clinical isolates in the kinetics of survival and in their ability to become antibiotic insensitive, suggesting a genetic basis for these differences. We are screening a PsA mutant library to find factors involved in intracellular survival that could be the basis for the development of novel anti-infectives.
The role of regulatory T cells in the Leishmania (Viannia) panamensis mouse model: a target for immunotherapy. (P3091)
Authors: Ehrlich Allison , Castilho Tiago , Goldsmith-Pestana Karen , Sparwasser Tim , McMahon-Pratt Diane 
Published: January 2023

Abstract
Leishmania (Viannia) parasites are etiological agents of cutaneous leishmaniasis in the New World. Infection in humans is characterized by mixed Th1/Th2 and hyperinflammatory responses. Treg suppressive function is diminished and only restored with disease resolution. Using the mouse model of chronic L. (V.) panamensis infection, we examined the hypothesis that Treg impairment contributes to pathogenesis. Upon infection, Treg CD4+Foxp3+ cell levels were reduced and dysregulated. Treg cells produced IFNγ and had a reduced ability to suppress T cell proliferation in vitro. Ablation of Tregs in DEREG mice resulted in enlarged lesions, increased parasite load and enhanced production of IL-17 and IFNγ. Conversely, adoptive transfer of Tregs from naïve mice halted disease progression, lowered parasite burden and reduced production of IL-10, IL-13, IL-17 and IFNγ. As Treg function appeared to be important for controlling pathogenesis, we examined whether directly modulating Treg function provided a target for immunotherapy. As a proof of principle, chronically infected mice were treated with high dose CpG to induce Tregs. Immediately after treatment, increases in TGFβ and Foxp3+ cells were observed, with an ablation of Foxp3+IFNγ+ cells and reduction of IL-10, IL-13, IL-17 and IFNγ. CpG treatment led to amelioration of disease. Thus, immunotherapy targeting Tregs may provide an alternate treatment strategy for leishmaniasis caused by L. (Viannia) panamensis parasites.
EBNA-1 specific effector T cell deletion associated with holoendemic malaria exposure in the etiology of endemic Burkitt’s lymphoma (P3063)
Authors: Mulama David , Chelimo Kiprotich , Collins Ouma , Jura Walter , Otieno Juliana , Vulule John , Munz Christian , Moormann Ann 
Published: January 2023

Abstract
Etiological mechanism of eBL remain largely unknown despite long-standing epidemiological link between malaria and EBV co-infection. Age-dependent deficiency in EBV-specific CD8+ T cell-mediated IFN-γ immunosurveillance has been reported in malaria holoendemic exposed children which has been associated with eBL diagnosis. We sought to investigate whether qualitative differences in EBNA-1 specific T cells existed in malaria-exposed children to explain their increased risk for eBL. We conducted a cross-sectional study of healthy children from western Kenya with divergent malaria exposure:Kisumu (holoendemic) and Nandi (hypoendemic) and eBL age-matched patients. T cell effector function was evaluated by multiparameter flow cytometry against T cell lineage markers(CD3,4,8,45RA & CCR7) and functional phenotype (IFN-γ, IL10, IL17 & PD1) to EBNA-1. EBNA-1 specific responses were compared to MSP-1, EBNA2 and EBNA3A. We found significantly higher IFN-γ responses to MSP1 in the eBL & Kisumu compared to Nandi children (p=0.03), in contrast to EBNA1, which were significantly lower in eBL and Kisumu compared to Nandi children (p=0.01). Responses to EBNA2 and EBNA3A did not differ between groups. IFN-γ was generated from CD4 TEM and a heterogeneous combination of CD8 T-cells. PD-1 expressing T-cells were less frequent in eBL patients and highest in Kisumu children.This suggests that the EBNA1-specific deficiencies are due to deletion of T-cell population due to malaria induced exhaustion.
mTORC1 inhibition pronounces CD8 T cell effector defects in aging (P1233)
Authors: Goldberg Emily , Smithey Megan , Nikolich-Zugich Janko 
Published: January 2023

Abstract
Mammalian target of rapamycin complex 1 (mTORC1) is a critical cell nutrient sensor and its role in CD8 T cell development, homeostasis, and fate decisions during infection are becoming increasingly evident. Seminal studies showed that direct mTORC1 inhibition with rapamcyin favored memory CD8 T cell development after infection. Simultaneously, rapamycin was shown to extend lifespan in mice. Whether or not rapamycin treatment alters the CD8 T cell immune response in old mice has not been studied. This question is particularly critical given recent data from our lab that CD8 T cell defects after Listeria monocytogenes (Lm) and West Nile Virus infection are both associated with increased infection mortality in old mice. Therefore, we tested the effect of rapamycin (75μg/kg), when given during the T cell priming phase, on CD8 T cell effector responses in adult (3 months) and old (18 months) mice infected with Lm. We found that mTORC1 inhibition with rapamycin significantly inhibited effector differentiation of antigen-specific CD8 T cells and this was especially pronounced in old mice. Additionally, contrary to previous reports, we measured no benefit on CD8 T cell memory formation in either old or adult mice. Therefore, we conclude that any beneficial effects of rapamycin on memory formation likely come at the cost of effector function, and these effects may be pathogen-specific. Furthermore, rapamycin may not be a suitable candidate for extending lifespan or “Healthspan.”
Cell-extrinsic mechanism of CTLA4-mediated regulation of dendritic cell maturation depends on STAT3 (P1202)
Authors: Zhang Li , Kowalczyk Aleksandra 
Published: January 2023

Abstract
The role of cytotoxic T lymphocyte antigen 4 (CTLA4) in hampering immune responses has been well documented; however, the exact mechanism by which CTLA4 exerts its effect is still under debate. Here, we investigated whether CTLA4 signal alone is sufficient to inhibit dendrtic cell (DC) maturation, stimulatory function, and the molecular mechanisms involved. We demonstrate that stimulation of DCs with CTLA4, either expressed by inducible regulatory T cells (iTregs) or by cross-linking with CTLA4Fc fusion protein, is sufficient to inhibit LPS-induced maturation of both mouse and human DCs. The CTLA4 signaling significantly decreased DC CD80 and CD86 expression as determined by flow cytometry, real-time PCR and Western blot analyses. Importantly, CTLA4Fc-treated DCs had reduced ability to stimulate T cell proliferation and cytokine production in both syngeneic and allogeneic settings. Furthermore, we identified a novel reverse signaling pathway that is dependent on direct activation of STAT3 in DCs and subsequent suppression of NFκB activity. Our data demonstrate, for the first time, that a reverse signal induced by CTLA4 is sufficient to suppress LPS-induced DC maturation and function. This work opens new windows for generation of tolerogenic DCs that could ultimately be used for treating autoimmune diseases and transplant rejection.
Raf-1 kinase inhibitor protein: an important molecule for modulating inflammatory responses? (P1188)
Authors: Wright Kyle , Vella Anthony 
Published: January 2023

Abstract
Systemic inflammatory response syndrome is a costly burden for health care systems both nationally and globally. SIRS results from the systemic release of exorbitant quantities of proinflammatory cytokines, which leads to severe complications including acute lung injury, multiple organ dysfunction syndrome, and even death. RKIP is a regulator of MAPK and NF-κB signaling cascades which are both critical for production of the cytokines responsible for SIRS initiation. Using a T cell dependent mouse model of SIRS, we have shown that RKIP is necessary for the synthesis of pathologic quantities of IFNγ from antigen specific CD8+ T cells, but not CD4+ T cells, which is due to an intrinsic signaling defect downstream of the TCR in RKIP-/- T cells. Importantly, RKIP deficient mice were able to mount a productive response to vaccination, suggesting that RKIP may be critical for cytokine production during serial TCR triggering in SIRS, but less so during primary T cell responses (data submitted for publication). Additionally, we have found that RKIP may also play a role in antigen presenting cell function. This is evidenced by a rapid, but transient, inability to detect RKIP by western blot after stimulation of splenocytes with TLR ligands. Although an exact molecular mechanism underlying RKIP’s effects is presently unclear, we are currently utilizing cutting-edge PF 2D proteomic mapping to further elucidate its role within the signaling machinery of immune cells.
Easy, column-free procedure for the enrichment of human Th1 cells from peripheral blood (P3239)
Authors: Fairhurst Maureen , Yu Jessie , de Jong Susan , Thomas Terry 
Published: January 2023

Abstract
Upon activation naïve T helper (Th) precursor cells are polarized toward various cell subtypes and can be distinguished from each other based on effector function and chemokine expression. Th1 cells regulate cellular immunity via IL-2 plus IFN-γ, activating macrophages, cytotoxic T, NK and B cells in an effort to eliminate intracellular pathogens. Th1 cells preferentially express the chemokine receptors CXCR3 and CCR5 and can be further characterized by intracellular staining for IFN-γ. We have developed a 2-step EasySepTM immunomagnetic column-free method for the enrichment of CD4+CXCR3+ T cells from fresh peripheral blood nucleated cells. First, non-CD4 T cells are targeted for depletion using dextran-coated magnetic particles and a cocktail of antibody complexes. Labeled cells are separated using an EasySepTM magnet, and pre-enriched CD4 T cells are poured off. CXCR3+ cells are then positively selected from the pre-enriched fraction. The procedure can be automated using RoboSepTM. With an initial frequency of 10 ± 3% CD4+CXCR3+ cells, purities of 90 ± 4% (n=12) can be obtained. When stimulated, a high proportion of these cells produce IFN-γ (68 ± 12%) compared with total CD4 T cells and pre-enriched CD4 T cells. Less than 1% of isolated cells produce cytokines associated with other Th cell subtypes (IL-4, IL-17). Enrichment of unstimulated human Th1 cells enables the investigation of chronic inflammation responses and mechanisms of regulation in human models of disease.