bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signaling roles of Dictyostelium discoideum TirA in response to gram-negative bacteria (INM9P.450)
Authors: Snyder Michelle , White Theresa , Berlett Michael , Weichseldorfer Matthew , Shaw Emily , Zapf Ava , Snyder Greg 
Published: January 2023

Abstract
Innate immune Toll-like receptors (TLRs) signal via toll/interleukin-1 receptor (TIR) domains, resulting in initiation of various signaling pathways, including MAPK pathways. The model organism Dictyostelium discoideum, a social amoeba that phagocytizes bacteria for nutrients, lacks full-length TLRs but encodes for several TIR domain-containing proteins. One such protein, TirA, is required for the growth of D. discoideum in the presence of Gram-negative bacteria. Furthermore, addition of LPS increases D. discoideum’s bactericidal activities in a TirA- and ERK- dependent manner. Here we are investigating TirA’s role in the activation of ERK-MAPK pathways in response to bacteria and folic acid. ERK phosphorylation was found to be reduced in TirA-deficient cells as compared to WT cells in response to Gram-negative bacteria, but not in response to Gram-positive bacteria or to folic acid. Furthermore expression of uduB, a MAPK-regulated transcript, has previously been found to be upregulated in TirA-deficient cells during steady-state growth on Gram-negative bacteria. Here we show that upregulation of uduB can be detected within 4 h of exposure of TirA-deficient cells to Gram-negative bacteria. In addition to these procedures we are also working to solve the structure of D. discoideum TIR domains through the use of X-ray crystallography. By obtaining this structural information new insights into the conserved mechanisms of TIR domain signaling in may be revealed.
The imidazoquinoline TLR7 agonist negatively affects virus-induced type I and type III IFN induction pathways in primary human plasmacytoid dendritic cells (INM9P.452)
Authors: Natalia Mahwish , Dai Jihong , Singh Sukhwinder , Cui Chongwei , Fitzgerald-Bocarsly Patricia 
Published: January 2023

Abstract
Human pDC recognize Influenza/Flu and HSV through TLR7 and -9, respectively, resulting in production of type I and III IFN and pro-inflammatory cytokines. We observed that TLR7 is constitutively present in the ER and LAMP1-positive late endosomes in pDC, and upon stimulation with Flu, TLR7 co-localization with late endosomes increased. Synthetic small molecule TLR7 ligands from the imidazoquinoline family are being used for anti-viral therapy and as immune adjuvants. We investigated the mechanisms by which 3M003 induces type I and III IFN production in pDCs. We found that 3M003 induced IFNs much more rapidly than Flu or HSV, but at much lower levels. Surprisingly, neither the TLR7 inhibitor IRS661 nor cysteine endolysosomal protease inhibitor Z-FM-FMK affected 3M003 induced IFN production although both effectively inhibited Flu-induced IFN production. In addition, 3M003 inhibited Flu, HSV, HIV and CpGA induced IFN production in pDC when used together with these TLR7/9 agonists. However, 3M003 did not affect uptake by pDC. Interestingly, 3M003 inhibited virus-induced IRF7 nuclear translocation while enhancing its phosphorylation. Taken together, these results suggest that in pDCs, 3M003 utilizes signaling pathways distinct from HSV or Flu resulting in the different levels of IFN production.
CD4+CD25+ regulatory T cells inhibit NK cell hepatocytotoxicity of hepatitis B virus transgenic mice via membrane-bound TGF-beta and OX40 (IRC10P.464)
Authors: Chen Yongyan , Sun Rui , Wei Haiming , Tian Zhigang 
Published: January 2023

Abstract
Human healthy HBsAg carriers are susceptible to hepatocyte injury induced by a variety of elements, among which the immune responses and the negative regulation might be critical. It has been reported by us that HBV transgenic mice were oversensitive to liver injury after immunologic triggering and that NK cells played the critical role via NKG2D recognition of HBsAg positive hepatocytes. In this study, using the low dose of Con A-induced oversensitive liver injury model in HBs-Tg mice, it was found that the number of CD4+CD25+Foxp3+Treg cells was significantly increased in the liver after Con A stimulation, which was along with the recovery of liver injury. Adoptive transfer of hepatic Treg cells from HBs-Tg mice treated by Con A could significantly attenuate the oversensitive liver injury in recipient HBs-Tg mice induced by Con A, which was resulted from the inhibited activation of hepatic NK cells. Further, the expression of mTGF-beta was markedly higher on hepatic Treg cells of HBs-Tg mice, which could be further up-regulated by Con A stimulation. Simultaneously, the expression of OX40 on hepatic Treg cells was also up-regulated after Con A stimulation in HBs-Tg mice. Antibody blockade and cell transwell experiments further confirmed that Treg cells significantly inhibited NK cell hepatocytotoxicity of HBs-Tg mice via mTGF-beta and OX40/OX40L interaction. These results would be critical to reveal the mechanisms of immune injury and regulation during human HBV infection.
The immunomodulatory role of glycoprotein nonmelanoma clone B (GPNMB) in macrophage polarization in diabetes (IRC10P.465)
Authors: Yu Bing , Malcuit Christopher , Safadi Fayez , Kim Min-Ho 
Published: January 2023

Abstract
Diabetes is associated with a low-grade chronic inflammation, which has been linked with macrophage dysfunctions manifested by exaggerated pro-inflammatory M1 response and attenuated M2 response. The objective of this study is to validate glycoprotein nonmelanoma clone B (GPNMB) as an immunomodulatory factor that can regulate polarization of macrophages from diabetic mice. In an in vitro study of macrophages polarization, we have observed that GPNMB expression in macrophages from wild-type mice negatively correlates with the gene expression levels of the pro-inflammatory cytokines in which macrophages were induced to polarize into the inflammatory (M1: treatment with 100 ng/mL LPS and 20 ng/mL IFN gamma) or regenerative (M2: treatment with 20 ng/mL interleukin 4) phenotypes. In addition, we have found that polarized macrophages from db/db mice exhibited higher M1 markers and reduced M2 markers as compared with litter mate control mice. More importantly, the exogenous treatment of recombinant GPNMB protein (100ng/mL) could significantly attenuate the level of CD86 expression in M1 macrophages, upregulate CD206 expression in M2 macrophages, and increase the phagocytosis of apoptotic neutrophils by M2 macrophages from db/db mice, with responses that were comparable to those of control mice. Taken together, those results support that GPNMB could act as an immunomodulatory factor that can rescue aberrant functions of macrophages in diabetes.
Restoration of T lymphopoiesis from myeloid progenitors by targeting of C/EBPα (LYM7P.721)
Authors: Welner Robert , Czibere Akos , Yang Henry , Zhang Hong , Ye Min , Tenen Daniel 
Published: January 2023

Abstract
Loss of immune cell function with increased incidence of myeloid skewing and leukemia are well known features of the aging hematopoietic system. As one example, stem and progenitor cells (HSPCs) have greatly reduced potential to generate T lymphocytes. However, the underlying mechanisms are poorly understood. It was previously known that levels of the myeloid transcription factor C/EBPα rise with age and we asked if this might account for some of the previously described phenomena. C/EBPα deficient common myeloid progenitors (CMPs) had a distinct T cell gene expression signature that correlated with an increased potential for differentiation toward the T cell lineage. Moreover, the Notch signaling pathway activation was up-regulated in CMPs that were deficient in this transcription factor. To better understand the mechanisms underlying hematopoietic aging of T cell progenitors, we deleted C/EBPα in aged mice. Remarkably, that increased lymphoid differentiation of HSPCs in both culture and transplantation assays. These findings have implications for our understanding of the transcriptional wiring in lymphoid/myeloid progenitors. Additionally, the data support a model in which age-dependent alterations in gene expression affect lineage choice decisions and could sequentially cause immunosenescence and predispose the aged to myeloid leukemia.
The role of cytotoxic CD4+ T cells in controlling Salmonella. (MPF6P.741)
Authors: Kotov Dmitri , Nelson Ryan , Jenkins Marc 
Published: January 2023

Abstract
Cytotoxic CD4+ T cells (ThCTLs) recognize and lyse cells that express cognate peptide:MHCII ligands. We hypothesized that ThCTLs contribute to the control of chronic Salmonella, which persists in mucosal phagocytic cells that express MHCII. Using an in vivo cytotoxicity assay, we determined that Salmonella-infected mice contain CD4+ T cells capable of killing target cells pulsed with an MHCII-binding Salmonella peptide. In addition, we found that ~15% of Salmonella peptide:MHCII-specific CD4+ T cells express granzyme B and the Eomes transcription factor, which are markers of ThCTLs in other systems. We also discovered that many of the Salmonella specific ThCTLs express α4β7, an integrin important for mucosal homing. We are now poised for future work aimed at understanding the role that these cells play in controlling mucosal infection.
Protective capacity of CD8 T cells targeting a spectrum of Plasmodium-specific epitopes (MPF6P.735)
Authors: Doll Katherine , Pewe Lecia , Harty John 
Published: January 2023

Abstract
Despite decades of research, malaria remains a global health crisis. Currently, the most advanced anti-malarial vaccine in human clinical trials (RTS,S) does not provide long-term, sterilizing immunity against Plasmodium infection. Plasmodium-specific CD8 T cells can provide sterilizing immunity to Plasmodium infection in rodent models. However, the numerical requirements for memory CD8 T cell protection against a defined epitope, P. berghei CS252-260 (a CSP epitope) exceeds 1% of peripheral blood lymphocytes - a 103-104 fold higher number than required for protection against some bacterial or viral infections. Recently, three novel H-2b-restricted Plasmodium-specific CD8 T cell epitopes were described from the following antigens: GAP50, S20, and TRAP. Priming with peptide-loaded mature dendritic cells followed by boosting with recombinant L. monocytogenes expressing these epitopes results in antigen-specific CD8 T cell responses constituting 0.3-6% of the PBL in CB6.F1 mice. The capacity of these single CD8 T cell responses to provide protective immunity in a stringent model of liver stage infection with P. berghei will be described. Moreover, we are determining whether combining multiple epitope-specific responses can reduce the total numerical requirement for CD8 T cell-mediated protection. These studies may aid in the preclinical design of a sterilizing CD8 T cell based anti-Plasmodium subunit human vaccine containing multiple CD8 T cell epitopes.
Antigen dependent checkpoints for generating a persisting effector CD8 T cell population during chronic parasite infection (MPF6P.737)
Authors: Chu Hamlet , Robey Ellen 
Published: January 2023

Abstract
We have previously shown that an immunodominant CD8 T cell response to a MHC class I Ld-restricted parasite antigen confers strong resistance against chronic T. gondii infection in mice. Here we show that despite its lower precursor frequency, this immunodominant T cell population is activated earlier, and expands more rapidly during the priming phase compared to the subdominant populations. The number of these T cells is maintained near their peak values throughout chronic infection, with no sign of a contraction phase. Moreover, this population maintained its effector functions and phenotypes without exhaustion. We identified a transient subset within this immunodominant T cell population, which survives, proliferates and gives rise to terminally differentiated effectors only in the presence of persisting antigen in vivo. We propose that the timing and quality of antigen presentation at the acute and chronic phases of infection are critical to the generation and maintenance of this subset, and thus to the overall protective ability of the immunodominant population.
Resident memory CD8 T cells are master orchestrators of protective innate and adaptive immune responses (MUC7P.765)
Authors: Schenkel Jason , Fraser Kathryn , Beura Lalit , Pauken Kristen , Vezys Vaiva , Masopust David 
Published: January 2023

Abstract
CD8 T cells eliminate intracellular infections through direct cytolysis, making them ideal candidates for vaccine design. Recent studies have shown that resident memory CD8 (TRM) are critical in mediating early local pathogen clearance after re-infection. However, given the numerical paucity of CD8 TRM relative to the total number of potential target cells, it is unclear how CD8 TRM could rapidly clear pathogen strictly through direct cytolysis. We therefore hypothesized that T cell activation precipitated local polyfunctional cytokines, which were important mediators of protection after local re-infection. Here, we demonstrate that after local antigen re-encounter, CD8 TRM reactivation within the female reproductive tract (FRT) elicited secretion of multiple cytokines, which induce rapid functional changes in multiple leukocytes. During this recall response, local secretion of IL-2 and IL-15 upregulated granzyme B in local lymphocytes, TNFα matured tissue dendritic cells, and IFNγ recruited circulating memory CD8 T cells and B cells to the FRT. Thus, CD8 TRM cells employ multiple polyfunctional cytokines to orchestrate diverse and parallel responses to infection, modulating both circulating and local leukocytes. Future studies will continue to dissect apart the diverse mechanisms CD8 TRM use to clear pathogen. Vaccines should therefore aim to establish CD8 TRM cells for efficacious adaptive and innate immune responses to pathogen.
Cornea-infiltrating dendritic cells are critical in CD8+ T cell expansion in the draining lymph nodes following ocular herpes simplex virus-1 infection (MUC7P.750)
Authors: Buela Kristine-Ann , Hendricks Robert 
Published: January 2023

Abstract
The cornea is a mucosal surface that has resident dendritic cells (cornea-resident DC) and DC infiltrate the cornea following herpes simplex virus-1 (HSV-1) infection (cornea-infiltrating DC). Both DC populations could theoretically carry viral antigens to the draining lymph nodes (DLN) for direct expansion of HSV-specific CD8+ T cells or for cross presentation by DLN-resident DC. The expanded CD8+ T cells infiltrate the trigeminal ganglion (TG) and prevent HSV-1 transmission to the brain and lethal encephalitis. Local depletion of cornea-resident DC in CD11c-DTR mice did not affect CD8+ T cell expansion (BrdU incorporation) in the DLN. However, continuous depletion of cornea-infiltrating DC abrogated CD8+ T cell expansion at 3 days post infection (dpi) and dramatically reduced their expansion at 7 dpi, leading to reduced numbers in the TG and increased mortality. Cornea-infiltrating DC in DLN showed increased expression of the costimulatory molecules CD70, CD80, and CD86. Blocking CD70 significantly reduced CD8+ T cell numbers in the DLN, by selectively inhibiting proliferation and survival of those reactive to subdominant HSV-1 epitopes, leading to decreased CD8+ T cell numbers in the TG and increased mortality. Our data are consistent with the notion that cornea-infiltrating DCs transport HSV-1 antigens to the DLN for direct presentation to and expansion of HSV-specific CD8+ T cells, and have a critical role in preventing lethal infections.
Neonatal mice failed to induce an effective adaptive immune response to methicillin-resistant Staphylococcus aureus (MUC7P.773)
Authors: You Dahui , Fitzpatrick Elizabeth , Cormier Stephania 
Published: January 2023

Abstract
The development of pneumonia in neonates due to infection by methicillin-resistant Staphylococcus aureus (MRSA) is associated with significant morbidity and mortality. Our lab has developed a neonatal mouse model of MRSA-induced pneumonia to investigate the pathogenesis of MRSA in neonates. Neonatal pups or adult mice were intranasally exposed to MRSA (USA300), and the pulmonary immune response was analyzed at various days post infection (dpi). We observed a decrease in the survival rate of neonates and an increase in bacterial load in the lungs of neonates in comparison to adult mice. The increase in bacterial load correlated with a decrease in the total number of cells in the bronchoalveolar lavage fluid, which corresponded to a decrease in macrophages and neutrophils in neonates compared to adults on 1dpi. By 6dpi, neonates failed to develop an effective Th1 response compared to the adults (1.3% CD4+/IFN-γ+ cells vs. 18% CD4+/IFN-γ+ cells). Also unlike the adults, neonates failed to mount a significant Th17 response (0.89% CD4+/IL-17+ vs. 2.6% CD4+/IL-17+). The failure of neonates to mount an efficient adaptive immune response correlated with a decrease in the frequency of DCs in the lung and with less mature DCs as determined by CD86 expression in comparison to adults. These studies suggest that the failure to induce a Th1 response in neonates results in their failure to control bacterial growth.
Hair follicles retain memory CD4+ T cells in skin following infection with herpes simplex virus-1 (MUC7P.774)
Authors: Collins Nicholas , Gebhardt Thomas , Carbone Francis 
Published: January 2023

Abstract
Skin is barrier tissue at the interface of our body and the environment that is exposed to pathogens and therefore must be efficiently protected. Hair follicles are abundant in skin and produce chemokines. However, whether these chemokines regulate skin T cells has not been explored. In the context of a localized viral skin infection with herpes simplex virus-1 (HSV-1), T cell infiltration is necessary for optimal skin protection. Following resolution of infection, memory T cells remain at sites of prior infection. In this study, effector memory CD4+ T cells as well as antigen presenting cells (APC) were found in higher numbers in previously infected ipsilateral skin at memory times compared to contralateral uninfected skin. Histology revealed that the majority of these cells were found in distinct aggregates surrounding hair follicles. The number of CD4+ T cells and APC per aggregate, as well as the frequency of follicular aggregates was increased on the ipsilateral side at memory compared to contralateral skin. Activated CD4+ T cells treated with pertussis toxin did not aggregate, indicating the requirement for chemokine signaling. Thus, hair follicles appear to play a key role in retaining anti-viral memory CD4+ T cells in the memory phase of the response in order to place these cells in an optimal location to respond to secondary viral infection.
Revisiting the role of B cells in Chlamydia muridarum genital tract infection (MUC7P.753)
Authors: Li Lin-Xi , McSorley Stephen 
Published: January 2023

Abstract
B cells can contribute to acquired immunity against intracellular bacteria, but do not usually participate in primary clearance. Using MHC class-II tetramers, we examined the endogenous CD4 T cell response to Chlamydia muridarum genital tract infection. Chlamydia-specific CD4 T cells expanded rapidly and persisted as a stable memory pool for several months after infection. While most lymph node Chlamydia-specific CD4 T cells expressed T-bet, a small percentage co-expressed Foxp3, and RORγt-expressing T cells were enriched within the reproductive tract. Local Chlamydia-specific CD4 T cell priming was markedly reduced in mice lacking B cells, and bacteria were able to disseminate to the peritoneal cavity, initiating a cellular infiltrate and ascites. However, bacterial dissemination also coincided with elevated systemic Chlamydia-specific CD4 T cell responses and resolution of primary infection. Together, these data reveal heterogeneity in pathogen-specific CD4 T cell responses within the genital tract and an unexpected requirement for B cells in regulating local T cell activation and bacterial dissemination during genital infection. We are currently focusing our efforts on understanding the mechanism underlying the function of B cells during primary Chlamydia infection. Our preliminary data suggest that antibody, but not B cell-dependent antigen presentation, is required for bacterial containment at local genital mucosa.
A HEXIM1-AIRE transcriptional counter-balance in trophoblasts regulates maternal-fetal mucosal immunity in pregnancy (MUC7P.755)
Authors: Wang Zhao-Yuan , Sun Guang , Faucette Azure , Unger Benjamin , Hong Peng , Yao Fayi , Guterman Jacqueline , Mathiarasu Aditya , Deng Jie , Tang Xiangna , Bluth Martin , Armant D. , Lum Lawrence , Siddiqui Maq , Chen Kang 
Published: January 2023

Abstract
Trophoblasts are gatekeepers at maternal-fetal mucosal interface, but trophoblast-derived molecules that initiate and maintain maternal-fetal mucosal immunity are not fully understood. We found that HEXIM1, an inhibitor of P-TEFb essential for eukaryotic RNA Pol II-mediated transcription, is highly expressed in human villous and extravillous trophoblasts. Hexim1-/- mouse placentas exhibit abnormal placental immunity characterized by increased maternal leukocyte and T cell infiltration, a paucity of spiral arteries and reduced placental size. HEXIM1 interacts in trophoblasts with AIRE, a protein critical for central and peripheral immune tolerance, via 7SK snRNA. Such interaction is further dependent on the nuclear localization domains of HEXIM1 and AIRE. Extravillous trophoblasts in human preterm labor with placental inflammation have reduced HEXIM1 and increased AIRE expression. Silencing HEXIM1 in trophoblasts led to increased Treg induction by trophoblasts. Our findings identify trophoblasts as a new type of extrathymic AIRE-expressing immunoregulatory cell, reveal a novel function of epithelial cells in mucosal immune regulation via AIRE-mediated Treg induction, suggest HEXIM1 and AIRE establish a transcriptional counterbalance in trophoblasts to maintain maternal-fetal mucosal immunity in pregnancy by regulating P-TEFb and Pol II, and promote a better understanding of how certain pathogens, such as HIV-1, perturb mucosal homeostasis after hijacking the HEXIM1 machinery.
Chronic exposure to cadmium alters gut immune homeostasis and innate immunity (MUC8P.810)
Authors: Kim Eunsoo , Jee Junbae , Steiner Haley , Cormet-Boyaka Estelle , Boyaka Prosper 
Published: January 2023

Abstract
Cadmium is a toxic heavy metal that can be ingested due to its presence in contaminated water and its accumulation in leafy vegetables, fish and grains. Since cadmium can compete with iron for intestinal absorption, long-term ingestion of cadmium can change composition of gut-commensal bacteria by inhibiting the growth of selected bacteria. Gut-commensal bacteria are critical to maintain intestinal homeostasis since they limit attachment of infectious agents, regulate pro-and anti-inflammatory milieu and secretory IgA levels. However, consequences of chronic exposure to cadmium for gut immune homeostasis, and mucosal innate immunity are poorly understood. To investigate the effect of cadmium on gut-homeostasis, C57BL/6 mice were treated with cadmium-contaminated water for 28 days. Mice exposed to cadmium exhibited a significant reduction of secretory IgA levels, which correlated with reduced expression of polymeric Ig receptor mRNA. These mice also showed increased intestinal permeability to macromolecules when compared to control untreated mice. The chronic exposure to cadmium also render these mice more responsive to oral administration of cholera toxin since the frequency of Paneth and goblet cells, as well as the levels of mucus production and anti-microbial mRNA responses seen 16 hours after ingestion of cholera toxin were higher than those of control mice. In summary, environmental pollutant cadmium is a major regulator of gut immune homeostasis and innate immunity.