bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disruption of Folliculin interacting protein-1 results in loss of sIg+ B cells and inhibits autophagy
Authors: Ramirez Julita , Tsang Mark , Margineantu Daciana , Iwata Terri , Hockenbery David M , Iritani Brian M 
Published: January 2023

Abstract
Folliculin interacting protein-1 (Fnip1) was discovered through its interaction with Folliculin (Flcn), a tumor suppressor mutated in the rare disorder Birt-Hogg Dubé syndrome. The Fnip1/Flcn complex interacts with the catabolic regulator AMP kinase. Previous studies have shown that Fnip1 is required for the development of B-cells past the late pre-B stage (Park et al Immunity 2012) and for the development of invariant natural killer T (iNKT) cells (Park et al PNAS 2014). We previously found Fnip1-deficient immune cells exhibited concurrently increased activation of mTORC1 and AMPK. In this study, we used a floxed Fnip1 allele combined with poly inosine:cytosine (poly I:C)-inducible Mx1-Cre to investigate the effects of conditional Fnip1 depletion on immature and mature B cells, and utilized genetic experiments to investigate the mechanism(s) of the B cell developmental block. We show loss of sIg+ B cells in the bone marrow and spleen after conditional Fnip1 depletion. Fnip1-deficient B cells exhibited significantly increased metabolism (oxidative phosphorylation and glycolysis) upon stimulation, possibly as a result of increased mitochondrial number and mTOR activation. Bcl-xL and c-Myc overexpression rescued a small fraction of sIg+ B cells in Fnip1-deficient mice, while p53 deficiency (Trp53−/−) and mTORC1 inactivation (Raptorfl/flmb1-cre) did not. Finally, we show that Fnip1-deficient B cells expressing LC3-GFP have lower mean GFP fluorescence and do not respond as robustly as wild type B cells to induction of autophagy. These results suggest that Fnip1 mediates autophagy in B cells, and that tight regulation of autophagic flux is necessary for development and survival of immature and mature B cells.
Differential apoptosis sensitivity of human effector CD8+ T cells derived from central versus effector memory subsets in response to IL-2 withdrawal
Authors: Larsen Sasha E , Voss Kelsey , Snow Andrew L 
Published: January 2023

Abstract
CD8+ central memory (CM) and effector memory (EM) T cell subsets exhibit well-established differences in proliferative and protective capacity after infectious challenge. However, their relative sensitivity to apoptosis has been largely overlooked, despite the importance of programmed cell death in regulating effector T cell homeostasis. Here we demonstrate that primary human effector T cells derived from the CD8+ EM subset exhibit significantly higher sensitivity to cytokine withdrawal induced cell death (CWID), a critical intrinsic apoptosis program responsible for culling cells once an infection is cleared and interleukin-2 (IL-2) levels diminish. Interestingly, we found no differences in the expression of IL-2 or IL-2 receptor components in cells originating from either subset. Relative to CM-derived effectors, however, EM-derived T cells display more mitochondrial instability and greater basal caspase activation. Indeed, we found that heightened CWID sensitivity in EM-derived effectors is linked to higher expression of the pro-apoptotic Bcl-2 family protein BIM, both at steady state and with de novo induction following withdrawal of exogenous IL-2. These data point to “imprinted” differences in BIM protein regulation preserved between CD8+ CM and EM progeny that govern their relative sensitivity to CWID. These findings offer new insight into why CM-derived T cells display superior effector cell expansion and more persistent memory responses in vivo relative to EM-derived T cells, based on differential apoptosis sensitivity.
Despite KLRG1 expression, highly cytotoxic ThEO/TcEO polarized T cells efficiently establish immunologic memory
Authors: Bartkowiak Todd , Jaiswal Ashvin R , Ai Midan , Budhani Pratha , Ager Casey , Curran Michael A 
Published: January 2023

Abstract
Targeting immune inhibitory (CTLA-4, PD-1) or stimulatory (OX-40, 4-1BB) co-receptors has proven to be a potent anti-cancer therapeutic strategy, eliciting robust anti-tumor T cell responses and yielding compelling pre-clinical and clinical data in a variety of cancers. We have previously shown in pre-clinical models that 4-1BB agonist antibodies engender strong anti-tumor T cell responses capable of driving regression of established tumors and durable tumor-free survival. This impressive anti-tumor effect is due, in part, to the unique ability of 4-1BB co-stimulation to differentiate a novel subset of T cells that acquires a highly cytotoxic effector profile typically only seen in NK cells. This phenotype- known as ThEO (CD4+) or TcEO (CD8+)-is driven by the T-box transcription factor Eomesodermin, and is further characterized by expression of the inhibitory receptor KLRG1. We show here that, despite high level effector function and expression of several co-inhibitory receptors (PD-1, TIM-3, KLRG1), these ThEO/TcEO phenotype T cells efficiently establish immunologic memory and recall with high frequency upon secondary tumor challenge. Further, they maintain high effector function on recall and can traffic to tissue sites far removed from the original malignancy. These findings provide mechanistic insight into the process of memory formation and give evidence for the capacity of ThEO/TcEO cells to prevent tumor recurrence.
The adaptor molecule BCAP is essential for the formation of CD8+ T cell memory
Authors: Singh Mark Dharam , Hamerman Jessica A , Campbell Daniel J. 
Published: January 2023

Abstract
Generation of effector and memory CD8+ T cells is pivotal for the clearance of intracellular infections and forms the basis for vaccination strategies against a wide range of pathogens and anti-cancer immunotherapy. We have generated novel data which shows that the signaling scaffold protein B cell adaptor for PI3-kinase (BCAP) is upregulated in activated CD8+ T cells, links TCR/CD3 engagement to the PI3K signaling cascade and is essential for CD8+ T cell memory formation. To analyze the cell intrinsic properties of BCAP in CD8+ T cells, we used OT-1+ mice which have a high affinity CD8+ T Cell Receptor (TCR) for the ova peptide. We transferred 5,000 WT OT-1+CD45.1+cells and 5,000 BCAPKO OT-1+CD45.2+ cells into CD45.1+CD45.2+ recipients, then infected with Listeria Monocytogenes expressing the ova peptide. We found that BCAP is essential for the proper clonal expansion of CD8+ T cells and BCAP deficiency in CD8+ T cells resulted in a loss of KLRG1+CD127− Terminal Effector Cells (TECs) in favor of KLRG1− CD127+ Memory Precursor Cells (MPCs) in vivo. Strikingly, we observed an enhanced CD8+ T cell contraction phenotype in BCAP deficient CD8+ T cells which led to a significant loss of antigen-specific memory CD8+ T cells. BCAPKO CD8+ T cells were undetectable in 50% of all mice analyzed at day 100 post infection. Therefore BCAP is critical for the formation of CD8+ T cell memory. We found the greatest loss of cells was confined to the recently described KLRG1+CD27loCXCR3loEomeslo effector memory cells, which have potent cytolytic function and anti-cancer capabilities. Finally we found that the ability of BCAPKO memory CD8+ T cells to respond to secondary infection was dysregulated. To conclude, BCAP is essential for the formation of CD8+ T cell memory.
Control of TH17 and Treg balance by RhoGTPase Cdc42
Authors: Kalim Khalid Wasim , Yang Jun-Qi , Li Yuan , Zheng Yi , Guo Fukun 
Published: January 2023

Abstract
Balanced Th17 and regulatory T (Treg) cell differentiation and function are important for normal immunity and avoidance of autoimmunity. Cdc42 of the Rho GTPase family is an intracellular signal transducer that cycles between an inactive GDP- bound form and an active GTP-bound form under tight regulation. We have recently reported that Cdc42 is required for thymocyte development but suppresses Th1 cell differentiation, with no effect on Th2 cells. In this study, we further examined the role of Cdc42 in Th17 and Treg cell differentiation, using a T cell-specific Cdc42 conditional knockout mouse model. Cdc42 deficiency led to an enhanced Th17 differentiation evidenced by increased IL-17+ cells with increased STAT3 phosphorylation, under in vitro Th17 polarizing condition. In the absence of Cdc42, Foxp3+ cells were drastically reduced under in vitro Treg polarizing condition accompanied by less phosphorylation of Smad2 and Smad3 transcription factors. Functionally, in vitro Treg suppression assay found that Cdc42-deficient Treg cells were impaired in their suppressive activity. In both DSS induced colitis and naïve T cell transfer model of colitis in vivo, Cdc42 deficiency led to an exacerbated disease severity and increased infiltration of Th17 and Th1 cells with less Tregs in spleen, mLN and lamina propria of colon. Finally, Treg cell-specific deletion of Cdc42 resulted in systemic autoimmunity with reduced Treg cells and accordingly spontaneous T cell activation and increased IL-17+IFNγ+ double positive cells. In summary, our data have provided new insights into the regulation of the balance between Th17 and Treg differentiation and identified Cdc42 as a potential molecular target for the treatment of colitis.
Functional evidence for TCR scanning of MHC.
Authors: Kuhns Michael S , Parrish Heather 
Published: January 2023

Abstract
αβ T cells recognize antigenic peptides within their positively selecting self-MHCI or MHCII. While MHC-restriction is well established, the nature of the TCR-MHC interactions that mediate this phenomenon are intensely debated. One possibility is that clonotypic TCRs are positively selected based on their ability to recognize self-peptides within self-MHC (pMHC) in a lock-and-key fashion. Such TCRs would then be limited to scanning for antigenic peptides among those shapes that resemble the selecting pMHC. Alternatively, every TCR may poses germline-encoded specificity for most if not all allelic variants of both MHCI and MHCII. This would allow most TCRs to scan the contents of most MHC for peptides that could mediate positive selection or T cell activation depending on the contributing co-receptor (i.e. CD4 or CD8). Here we asked if increasing the frequency of Lck-associated CD4 molecules in T cell hybridomas would allow for the detection of sub-threshold TCR-MHC interactions that constitute scanning. The reactivity of ten distinct TCRs was assessed in response to selecting and non-selecting MHCII bearing “shaved” peptides with alanine substitutions at TCR contact residues: three of the TCRs were selected on MHCII, two were selected on MHCI, and five were generated in vitro without defined selecting MHC. IL-2 production was observed when each TCR interacted with selecting or non-selecting MHCII presenting shaved peptides. These data provide evidence of TCR-MHC interactions that are independent of the selecting MHC class, allele, or the sequence of the peptide presented by the MHC. We interpret these data as functional evidence for TCR-intrinsic specificity for MHCII.
The MAP kinase, tumor progression locus 2 (Tpl2), activates the Akt/mTOR/S6 ribosomal protein pathway, inhibits Foxp3 expression and limits Treg immunosuppressive functions.
Authors: Li Xin , Acuff Nicole V , Peeks Angela , Kirkland Rebecca , Nagy Tamas , Watford Wendy Tharpe 
Published: January 2023

Abstract
The serine-threonine kinase, tumor progression locus 2 (Tpl2 or Map3k8/Cot), is a potent inflammatory mediator that drives the production of TNF alpha, IL-1 beta, and IFN gamma. We previously demonstrated that Tpl2 modulates TCR signaling and T helper cell differentiation. However, little is known about how Tpl2 alters the development or function of regulatory T cells (Tregs). Tregs are a specialized subset of T cells that express Foxp3 and possess immunosuppressive properties. Because of Tpl2’s role in promoting inflammation, we hypothesized that Tpl2 inhibits Treg development and immunosuppressive functions. Tpl2−/− naïve CD4 T+ cells preferentially differentiated into Foxp3+ inducible Tregs in vitro as well as in vivo in a murine model of OVA-induced systemic tolerance. Treg biasing in Tpl2−/− T cells depended upon the TCR signal strength and correlated with reduced activation of the Akt/mTOR/S6 pathway. Importantly, freshly isolated Tpl2−/− Tregs had increased expression of Foxp3 and immunosupressive cytokines IL-10 and IL-35 and were more suppressive in a T cell transfer model of colitis, as evidenced by reduced accumulation of inflammatory T effectors, systemic inflammatory cytokines TNF, IL-6 and IFN gamma, and colonic inflammation. Therefore, Tpl2 promotes inflammation in part by limiting Foxp3 expression, iTreg differentiation and immunosuppressive functions. These findings suggest that Tpl2 inhibition may be used to preferentially drive Treg induction and limit inflammation in autoimmune diseases.
EphA2 prevents breakdown of the blood-brain barrier in experimental cerebral malaria.
Authors: King Thayer , Mimche Patrice , Bray Christian , Brady Lauren , Meyer Esmeralda , Galinski Mary , Lamb Tracey 
Published: January 2023

Abstract
Cerebral malaria (CM) is a leading cause of death from Plasmodium falciparum infection, yet the mechanisms of disease pathology are poorly understood. While Eph receptors have been linked to several neurological disorders, their roles in malaria remain largely unknown. Experimental cerebral malaria (ECM) is a lethal condition resulting from Plasmodium berghei ANKA (PbANKA) infection of mice on a C57BL/6J background that recapitulates key features of human CM including blood-brain barrier (BBB) breakdown. Here we show that PbANKA-infected EphA2 −/− mice, but not EphA2 +/+ mice, have an intact BBB at ECM onset. CD8+ T cells mediate ECM development, and EphA2 −/− mice exhibit less accumulation of CD8+ T cells in the brain despite normal splenic expansion providing a mechanism by which EphA2 deficiency may preserve BBB integrity. Upregulation of EphA2 mRNA in brains of PbANKA-infected C57BL/6J mice is a feature of ECM absent in non-lethal Plasmodium infections such as PbNK65 where CD8+ T cells are present in the brain but do not disrupt the BBB. Unlike EphA2 +/+ mice, PbANKA-infected EphA2 −/− mice are protected from death even with peripheral and organ-sequestered parasite levels similar to EphA2 +/+ mice suggesting BBB integrity, not parasite burden, is responsible for improved survival in EphA2 −/− mice. Therapeutically targeting EphA2 by blocking EphA2 activation or interaction with membrane-bound ephrin-A ligands on T cells leads to increased survival of PbANKA-infected C57BL/6J mice. We also observe a parasite-dependent upregulation of both ephrin-A mRNA in CD3+ human PBMCs and EphA2 mRNA in human brain endothelial cells. Taken together, our data suggests a novel and crucial role for EphA2 in ECM with potential translation to human CM.
Neutrophils license antifungal monocyte responses via carbonic anhydrase 4 modulation
Authors: Rivera Amariliz , Espinosa Vanessa , Dutta Orchi , Henry Everett K , Siracusa Mark C 
Published: January 2023

Abstract
Neutropenia is a significant risk factor for life threatening invasive fungal infections (IFI). Neutrophils are well known as important innate cells that promote the direct eradication of fungal pathogens but whether they mediate antifungal defense beyond their role as effectors is unclear. Here we demonstrate that a pulmonary infection with the clinically relevant fungal pathogen Aspergillus fumigatus induces the diversification of specialized antifungal neutrophils that are required for antifungal CCR2+ monocyte-derived dendritic cell (mo-DC) function. Selective depletion of neutrophils resulted in global transcriptional alterations of the antifungal CCR2+ monocyte response, limited mo-DC differentiation, and diminished conidiacidal activity. Impaired mo-DC antifungal activity in neutropenic mice was accompanied by significant upregulation of carbonic anhydrase 4 (Car4) expression in CCR2+ monocyte precursors. Pharmacological inhibition of Car4 with the FDA-approved drug methazolamide (MZ) rescued the antifungal response of mo-DC and protected neutropenic mice from invasive apergillosis. Thus, beyond their role as effectors, antifungal neutrophils facilitate antifungal mo-DC functions by regulating Car4 activity. Moreover, our data provide proof-of-principle evidence for the importance of carbonic anhydrases in shaping innate cell differentiation as well as for the off-label therapeutic benefit of carbonic anhydrase inhibitors to boost antifungal immunity in susceptible patient populations.
Inflammation and immune cell recruitment in the CNS following disseminated Cryptococcus neoformans infection
Authors: Neal Lori M , Xing Enze , Xu Jintao , Osterholzer John J , Olszewski Michal A 
Published: January 2023

Abstract
Mortality in Cryptococcus neoformans (Cn) infection is chiefly associated with CNS infection but little is known about immune responses against Cn within the CNS. We established an i.v. model of disseminated cryptococcosis that leads to a rapid expansion of Cn in the CNS in order to compare inflammatory readouts in resistant CBA/J with susceptible C57BL/6 mice. Fungal burdens peaked (&gt;107CFU) in the brain by d7 post infection in both models, but in CBA/J mice fungal burden significantly declined between d14 to d21. In contrast, C57BL/6 mice developed persistently high fungal burdens through d21. Consistent with these findings CBA/J mice showed gradual increases in Ly6C+ myeloid, CD4+ and CD8+ T cell infiltration along with production of CCL2, IFNγ and CXCL10, reaching maximum or near maximum levels by day 14. In C57BL6, the development of inflammatory responses was significantly delayed. Production of cytokines and influx of Ly6C+, CD4+ and CD8+ cells was almost absent until d21, but prominently exceeded all readouts from CBA/J at day 21 by several fold. Significant increases in iNOShi CD11bhi MHCIIhi CD11c+ cells and an overabundance of highly activated CD11c+ MHCII+ microglia, hallmarks of rapidly developing CNS pathologies, were also more evident in the brains of C57BL/6 mice at d21. In summary, our findings are consistent with the hypothesis that early recruitment and activation of inflammatory cells in the CNS post-Cn infection, presumably in response to early CCL2-induction, along with subsequent early induction of IFNγ and CXCL10 promotes fungal clearance. In contrast, delayed responses found in C57BL6 mice were ineffective at removing fungal organisms while leading to over exuberant inflammation and detrimental CNS pathology.
Neutrophil recruitment during Leishmania infection: The role of sand fly salivary proteins
Authors: Guimaraes Anderson , Wen Xi , Carvalho Augusto Marcelino , Brzostowski Joseph , Valenzuela Jesus , Oliveira Fabiano 
Published: January 2023

Abstract
Neutrophils are the first cells recruited to the site of an infected sand fly bite and interact with Leishmania parasites. It has been proposed that the recruitment of neutrophils to the site of the bite increases the ability of Leishmania to establish an infection. Here we investigate the effect of sand fly salivary proteins on neutrophil recruitment. We purified bone marrow neutrophils from C57BL/6 mice or from peripheral blood of healthy human donors. Chemotaxis driven by sand fly saliva of vectors of visceral (Lutzomyia longipalpis) or cutaneous (Phlebotomus duboscqi) disease was measured by modified Boyden chamber assay and by imaging with the EZ-TAXIScan assay. Neutrophils migrated towards saliva glands of the vectors P. duboscqi and L. longipalpis, in a dose-dependent manner. Proteinase K treatment of saliva completely abrogated neutrophil recruitment, suggesting a protein as the chemotactic factor. To unearth the identity of the chemotactic factor, we have generated plasmids coding for the 20 most abundant salivary proteins from P. duboscqi and injected them in the ears of C57BL/6 mice. Neutrophil recruitment was analyzed by flow cytometry staining. We have identified 3 different salivary protein-coding plasmids with neutrophil recruitment activity. Finally, we have produced these 3 recombinant proteins in the HEK293 cell line system and we observed that a family of 40kDa salivary proteins acts as chemokines for neutrophils. We plan to validate the role of the salivary chemotactic factor in vivo and test if its neutralization can alter Leishmania infection. We put forward the hypothesis that blockage of this protein will disrupt neutrophil migration early in the Leishmania infection possibly altering the disease outcome.
Exosomes in human semen impair antigen-presenting cell function and decrease antigen-specific T cell responses
Authors: Vojtech Lucia N , Hughes Sean , Levy Claire , Taber Alexandria , Calienes Fernanda , Hladik Florian 
Published: January 2023

Abstract
Exposure to semen is the primary route of transmission for many sexually transmitted infections. Accumulating evidence suggests that components in semen directly impair leukocytes, which could compromise the protective efficacy of vaccine-induced immune responses in the mucosa. Exosomes, small microvesicles with immunomodulatory functions, are present at an average concentration of 2.2 × 1013 particles per ejaculate (n = 18). These seminal exosomes (SE) efficiently and rapidly entered peripheral and vaginal dendritic cells (DCs), whereas T cell uptake was poor. In PBMC cultures, SE impaired memory T cell function, reducing the production of TNF-alpha, IL-2 and/or IFN-gamma in response to virus-derived peptides an average of 60% for CD4+ T cells and 48% for CD8+ T cells, in a dose-responsive manner (n = 6). Reduction of cytokine production by memory CD8+ T cells was reduced to a greater extent for protein antigens as compared to peptide antigens, implying that antigen-presenting cell function was impaired by the presence of SE. Exposing only DCs, as opposed to bulk PBMCs, to SE also blocked subsequent CD8+ memory T cell activation, reducing the proportion of cells making cytokines by 22% (n = 5 donors). Expression of CD107a, a marker of cytotoxic T cell degranulation, was decreased by 42% in PBMC cultures exposed to SE and superantigen (n=4). SE also impaired vaginal T cell cytokine and degranulation responses to superantigen. Thus, SE likely inhibit antigen-specific T cell responses by impairing antigen-presenting cell function. Understanding how programmed immune responses are altered by the presence of semen is important to developing the next generation of vaccine and preventative treatments against sexually transmitted disease