bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blockade of diacylglycerol transferase 1 reprograms lipid accumulation in myeloid-derived suppressor cells and suppressed tumor progression
Authors: Adeshakin Adeleye Oluwatosin , Yan Dehong , Adeshakin Funmilayo O. , Zhang Mengqi , Afolabi Lukman O. , Wan Xiaochun 
Published: February 2023

Abstract
Immunotherapy, a way of restoring immune response and anti-cancer immunity, has revolutionized cancer therapy. However, immunosuppressive cells such as myeloid-derived suppressor cells (MDSC) still represent a significant impediment to immunotherapy, contributing to therapy failure and poor clinical responses. We previously reported that uptake of polyunsaturated fatty acid (PUFA) by MDSCs led to lipid accumulation via upregulation of fatty acid transport protein 2 (FATP2) to induce ROS-mediated immunosuppressive function thereby impairing T-cells activation to demonstrate their anti-tumor effect. Here lipidomics analysis revealed the exact lipid species accumulated in MDSCs from tumor-bearing tissues to be phospholipids and triglycerides (TAG). Interestingly, we observed significantly increased expression of a key enzyme involved in TAG synthesis - diacylglycerol transferase 1 (DGAT1), in MDSCs of Lewis lung carcinoma (LLC) and melanoma (B16F10)-bearing mice. Inhibiting DGAT1 reduced neutral lipid accumulation in MDSCs. Also, DGAT1 blockade downregulated MDSCs immunosuppressive genes and decreased MDSCs immunosuppressive function. Remarkably, blockade of DGAT1 expression reduced MDSCs and macrophages, thus abrogated tumor growth. Altogether, our study identified an unreported lipid metabolic target in MDSCs that promises a novel therapeutic option in clinical settings to enhance cancer immunotherapy.
This work was supported by the National Key R&D Program of China (2019YFA0906100), National Natural Science Foundation of China (Grants 82071772, 81501356 and 81373112), Key-Area R&D Program of Guangdong Province (2019B020201014).
Negatively charged nanoparticles inhibit tumor growth by altering tumor-associated macrophages and cancer-associated fibroblasts
Authors: Donthireddy Laxminarasimha Reddy , Vonteddu Prashanthi , Elhofy Adam , Gabrilovich Dmitry I 
Published: February 2023

Abstract
In this study, we show that a negatively charged biodegradable nanoparticles, CNP-301, have strong anti-tumor activity in several tumor models. This effect appears to be driven by shifting polarization of tumor associated macrophages (TAMs) to an anti-tumor M1 type and by downregulation of pro-tumorigenic cancer associated fibroblasts. Moreover, we show that CNP-301 treatment induces apoptosis of cancer associated fibroblasts (CAFs) in the tumor supporting a mechanism where perturbations of the TME and the associated stroma results in anti-tumor effects.
Development of surface engineered antigenic exosomes as vaccines for respiratory syncytial virus
Authors: Hong Suyeon , Ruan Shaobo , Greenberg Zachary , He Mei , McGill Jodi L 
Published: February 2023

Abstract
Human respiratory syncytial virus (HRSV) is one of the main drivers of lower respiratory tract illness in infants and young children worldwide. There are no licensed vaccines for HRSV available. Exosomes are cell-derived extracellular nanovesicles containing various biomolecules for intracellular communication. Exosomes secreted by antigen presenting cells such as dendritic cells can elicit immune responses by carrying MHC-I with antigenic peptide complex and other co-stimulating factors. Therefore, exosomes have emerged as potential vaccines to prevent viral infections or to treat cancers. Our prior work has demonstrated that a PDMS microfluidic culture chip device can be used to generate dendritic cell-derived tumor antigenic exosomes, with the capacity to activate tumor-specific CD8+ T cells. Herein, we further extended the work to surface engineer dendritic cell-derived exosomes with antigenic peptides from RSV (M187–195 and NS161–75). A mouse model of RSV infection was used to define the immunogenicity of surface engineered exosomes for activating virus-specific immune responses in vitro and in vivo. In vitro assays demonstrated that surface engineered exosomes successfully carried the engineered peptides of interest and had the capacity to elicit IFNγ production by activated, virus-specific CD8+ T cells. However, vaccination with engineered exosomes did not prime an in vivo activation of antigen-specific CD8+ T cell response, although surface engineered exosomes exhibit the safe administration. Additional experiments are necessary to optimize the potency of surface engineered exosomes as a vaccine platform for the prevention of viral infections such as RSV.
Reduce inflammatory cytokine profile in subspecialized neonatal APCs responding to viral pathogen-associated molecular patterns has implications for vaccine design
Authors: Lu Zhongyan , Guggenbiller Mathew , Tornbom Tora , Malloy Allison Marie Wahl 
Published: February 2023

Abstract
Young infants experience a higher burden of morbidity and mortality due to respiratory viruses and incomplete understanding of distinct age-dependent immune responses limits precision vaccine design in this age group. Subspecialized DCs and monocytes have evolved to detect viral pathogen-associated molecular patterns (PAMPs) to defend against infection and drive the adaptive immune response. We hypothesized that viral PAMPs and IFN I differentially activate neonatal DC and monocyte subsets resulting in age-dependent cytokine responses. To test this hypothesis, we isolated mononuclear cells from cord blood (CBMC) and peripheral blood (PBMC) and analyzed their responses through novel multiparameter spectral flow cytometric assays to PAMPs mimicking viral RNA. We discovered that conventional (c) DC2 in early life respond to Resiquimod (R848, TLR7/8 agonist) with similar upregulation of activation markers (CD80/86, CD70, CD38) and expression of TNFa, but more IL-6 compared to their adult counterparts. Unexpectedly, R848 and polyinosinic: polycytidylic acid (PIC, TLR3 agonist) resulted in significant CD25 upregulation by adult cDC2 and monocytes, in contrast to neonatal cells, suggesting decreased sensitivity to IL-2. In addition, in response to the antiviral type I IFN, cDC2 and monocytes from adults produced higher levels of CXCL10. Together our data suggest that neonatal DCs and monocytes have distinct functional responses to viral PAMPs, R848 and PIC, exhibiting reduced proinflammatory cytokine profiles. This may limit the potential for cytokine storm, but also delay the responsiveness to viral infections and vaccines that implement viral RNA in their design.
Transcriptional repressor BACH2 is a key regulator of stem-like CD8 T cells during chronic viral infection
Authors: Wu Tuoqi 
Published: February 2023

Abstract
During chronic viral infection and cancer, a CD8 T cell subset with stem-like characteristics maintains long-term T cell immunity and mediates the response induced by immune checkpoint blockade. The transcriptional and epigenetic programs of stem-like CD8 T cells diverged from those of other CD8 subsets early in the immune response. Using mice with chronic lymphocytic choriomeningitis virus (LCMV) infection, we found that the gene encoding transcriptional repressor BACH2 was highly expressed in stem-like CD8 T cells but was epigenetically silenced in terminally exhausted CD8 T cells early after infection. Ectopic expression of BACH2 enforced the transcriptional and epigenetic programs of stem-like CD8 T cells and restrained antiviral CD8 T cells in the lymphoid tissues. BACH2 deficiency impaired the differentiation of stem-like CD8 T cells and dysregulated their molecular program. We further demonstrated that BACH2 promoted stem-like CD8 T cell differentiation by suppressing BLIMP1 and RUNX3 pathways. In summary, our results showed that transcriptional repressor BACH2 drove stem-like CD8 T cell differentiation by guarding them against alternative cell fate.
CD25-targeted IL-2 promotes improved outcomes of influenza infection and boosts memory CD4 T cell formation
Authors: Strutt Tara M , Prokop Emily , Flores-Malavet Valeria 
Published: February 2023

Abstract
Interleukin-2 is a pleotropic cytokine with potent pro- and anti-inflammatory effects. These divergent impacts can be directed in vivo by forming complexes of recombinant IL-2 and anti-IL-2 monoclonal antibodies (IL-2C) to target IL-2 to distinct subsets of cells based on their expression of subunits of the IL-2 receptor. Herein we show that treatment of mice with a prototypical anti-inflammatory IL-2C, JES6-1-IL-2C, best known to induce CD25+ regulatory CD4 T cell expansion, surprisingly causes robust induction of a suite of inflammatory factors in the lung. However, treating mice infected with influenza A virus (IAV) with this IL-2C reduces lung immunopathology and is associated with marked expansion of regulatory CD4 T cells and innate lymphoid cells. We compare the spectrum of inflammatory proteins upregulated by pro- and anti-inflammatory IL-2C treatment and uncover a pattern of expression that reveals potential beneficial versus detrimental aspects of the influenza-associated cytokine-storm. Moreover, we show that JES6-1-IL-2C can deliver survival signals to CD4 T cells responding to IAV that improve their memory fitness, indicating a novel application of IL-2 to boost pathogen-specific T cell memory while simultaneously reducing immunopathology.
Role of heterotypic T cell memory following influenza re-challenge and secondary bacterial infection.
Authors: Cipolla Ellyse , Alcorn John F 
Published: February 2023

Abstract
Following recovery from influenza infection, an immunological T cell memory compartment is established. Memory T cells are able to respond and react to conserved pieces of the virus providing heterotypic strain protection. The role that cellular memory plays in influenza re-challenge is a topic of ongoing interest. The potential to harness cellular immune memory, in particular tissue resident memory, could provide researchers with the means to develop a universal influenza vaccine able to elicit a powerful immune response that is poised and localized in the lung environment.
Secondary bacterial infections in conjunction with influenza infection lead to increased instances of morbidity and mortality when compared to influenza infections alone. The role of heterotypic T cell memory and susceptibility to secondary bacterial pneumonias has yet to be elucidated. We hypothesize that prior exposure to influenza alters the memory response to a heterotypic super-infection re-challenge event. Mice were challenged with A/X-31(H3N2) and re-challenged 54 days later with strain A/PR/8/34 (H1N1), then challenged with MRSA on day 60. Sample analysis methods included histology, bacterial plating, flow cytometry, and RTPCR. Results suggest that mice with an established memory compartment are able to control secondary bacterial infections against MRSA as compared to their acute infected counterparts. Analysis of lung damage via histology also suggests that memory experienced mice are more protected from damage caused by secondary bacterial infection. This research suggests that the T cell memory compartment can limit the effects of bacterial super-infection in the context of heterotypic influenza strain challenge.
CD4 Effectors must re-encounter Antigen Locally in the Presence of Signals from Infection to Fully Differentiate into Specialized Tissue-restricted TFH and ThCTL effectors
Authors: Devarajan Priyadharshini , Vong Allen M , Castonguay Catherine H , Bautista Bianca L , Jones Michael C , Kugler-Umana Olivia , Swain Susan L 
Published: February 2023

Abstract
Functionally specialized, tissue-restricted CD4 effector subsets such as T helper cytotoxic cells (ThCTL) in the infected tissue and T follicular helper cells (TFH) in secondary lymphoid organs develop after Th1 and other effectors. Following influenza A virus infection, we find that CD4 effectors must recognize cognate Ag/MHC-II to become ThCTL and TFH but that this does not require a specific APC subset. While intrasplenic and intravenous Ag/APC delivery support spleen TFH, they do not support lung ThCTL or DLN TFH. Conversely, intranasal Ag/APC delivery supports lung ThCTL and DLN TFH indicating that Ag presentation in the site of residence is crucial. Strikingly, we find that continuing Ag-independent signals from infection are also needed for optimal generation of both subsets, even at this late effector phase. This contrasts with CD4 memory generation from effectors which is dependent only on Ag recognition and not on infection. Thus, this implies a pivotal checkpoint at which the fate of CD4 effectors is determined. In the absence of Ag most contract, while Ag alone can generate memory, and with continuing infection-mediated signals, distinct specialized effectors. This guards against unnecessary responses when pathogen is not present or has been cleared, but ensures the development of potent effectors in tissues if it persists. We propose that for vaccines to induce stronger immunity, they will need to be designed to provide additional presentation of CD4 T cell Ag and signals associated with infection at the effector checkpoint. This will provide the TFH needed for strong B cell Ab response and strong tissue-restricted CD4 T cell memory to ensure frontline response and broad, heterosubtypic protection.
STAT1 protects CD4 T cells from deletion by NK cells during influenza infection and promotes Th1 identity that can be enhanced through STAT4 to improve their anti-viral impact
Authors: Finn Caroline M , Dhume Kunal , McKinstry K Kai 
Published: February 2023

Abstract
Most CD4 T cells responding to influenza A virus (IAV) fit prototypical Th1 criteria including high expression of the transcription factor T-bet, the Th1 ‘master regulator’, and strong IFNg production. Optimal Th1 development in vitro also requires cytokine-dependent activation of the transcription factors STAT4 and STAT1, but how these pathways impact anti-viral responses is not clear. Here, to focus on the roles of CD4 T cell-intrinsic STAT4 and STAT1, we transferred STAT-deficient (STAT−/−) or wildtype CD4 T cells recognizing virus to congenic wildtype hosts, challenged with IAV, and analyzed donor effector responses in the infected lungs. STAT4−/− and wildtype cells reached similar numbers with no differences seen in their Th1 identity. In contrast, STAT1−/− donor cells were barely detected in host mice but reached similar numbers to wildtype donors when NK cells were depleted. Analysis of STAT1−/− cells in NK cell-depleted hosts revealed severely compromised Th1 identity that mirrored T-bet−/− donor cell responses. While these findings suggest that full Th1-polarization during IAV infection does not require STAT4, treatment of mice with IL-12 dramatically increases Th1 attributes in wildtype but not STAT4−/−CD4 T cells. This indicates that the wildtype IAV-primed CD4 T cell response is not strongly Th1-polarized. Finally, priming CD4 T cells in vitro with STAT4- and STAT1-activating cytokines promotes effector cells better able to combat IAV when transferred to unprimed mice than when only STAT1 activating signals are present. Enhancing Th1 identity through harnessing CD4 T cell-intrinsic STAT4 activation can thus improve their anti-viral impact during infection, with important implications for vaccine design.
Validating cell surface markers as accurate predictors of tissue residency
Authors: Scott Milcah C , Stolley J. Michael , Pierson Mark J , Wijeyesinghe Sathi , Gavil Noah Veis , Masopust David 
Published: February 2023

Abstract
Tissue resident memory T cells (TRM) represent the dominant antigen-experienced T cell subset that mediate local immunosurveillance in non-lymphoid tissues (NLT). Most accurately defined using migration assays, including parabiosis surgery and tissue grafting, TRM remain situated within NLT without recirculating through the blood. Such migration assays are challenging and often impossible to perform given animal-use approval or experimental constraints. These limitations have necessitated the use of cell surface markers such as CD69 and CD103 as surrogates for residency in the absence of more stringent approaches. Yet reliance on these cell surface markers alone often fails to accurately predict residency in tissues. As such, we performed a systematic interrogation of the correlation between flow cytometric staining profiles and the property of durable residence as assessed using parabiosis. In multiple infection models, we found that no consistent marker combination accurately identifies and captures the abundance and heterogeneity of TRM in diverse NLT. By evaluating the usefulness of cell surface markers as diagnostic of residency on a tissue- and infection-specific basis, we identified tissue specific phenotypes that reproducibly predicted residency in three infection models. These findings are important because refined analyses of TRM populations is key to addressing deficiencies in our understanding of how TRM mediate immunosurveillance. Ongoing work will further validate these tissue-specific phenotypes in additional infection models and ‘dirty mice’ that contain CD69+ T cells within the equilibrating T cell populations.
STAT1 gain of function mutation impairs immune response to viral infections
Authors: Philips Rachael Laura , Yao Chen , Milner Joshua D , Lionakis Michail S , O’Shea John J 
Published: February 2023

Abstract
Regulation of T cells by interferons and other cytokines, which act via STAT family transcription factors, is critical for host defense. Patients with STAT1 gain-of-function (GOF) mutations exhibit heightened STAT1 activation after cytokine stimulation and develop lifelong ailments, including chronic infections, autoimmunity, and cancer. A characteristic feature of this disorder is chronic mucocutaneous candidiasis (CMC), related to exagerated type 1/IFNγ bias that antagonizes a type 3/Th17 response required for fungal clearance. However, this type 1/IFNγ bias does not explain why almost 40% of reported patients exhibit chronic and sometimes lethal viral infections. This observation is unexpected, as cells with STAT1-GOF mutations exhibit increased expression of interferon stimulated genes following IFNα/β and IFNγ stimulation and patients show more IFNγ-producing CD4 T cells. This paradox emphasizes the critical need to understand basic principles of cytokine signaling, specifically how a STAT1-GOF mutation alters cytokine output. Using a novel conditional knock-in mouse expressing a common GOF STAT1 mutation, T385M, we found that this model recapitulates observations in patients (i.e. elevated STAT1 activation, increased total STAT1 protein, susceptibility to CMC), as well as a strong type 1/interferon bias at steady state. Despite this type 1 bias, STAT1-GOF exhibit impaired NK and CD8 T cell response to systemic viral infections. These results reveal that STAT1 activity must be tuned for proper immune response to viral infections.
Loss of the Class II Accessory Molecule HLA-DO leads to altered TCR avidity
Authors: Welsh Robin A , Song Nianbin , Foss Catherine , Sadegh-Nasseri Scheherazade 
Published: February 2023

Abstract
HLA-DO (DO in human; H2-O in mice) is a highly conserved non-classical MHC class II accessory molecule. Unlike the main Class II peptide editor HLA-DM, expression of DO is restricted to the thymic medulla, B cells and certain dendritic cell subsets. Although DO forms a stable complex with HLA-DM, its biological functions remain poorly understood. Previously, our lab provided biochemical evidence in support of a model where DO enhances the binding of DM-resistant peptides, and reduces the binding of DM-sensitive peptides to the HLA-DR1 (DR1) molecules in vitro. Changes in the quantities of either DM-resistant of DM-sensitive peptides could therefore lead to alterations in both thymic deletion, and peripheral activation of CD4 T cells. Here, using both in vivo antigen presentation as well as a novel avidity measurement tool, z-Movi™ (LUMICKS), we found that: (1) brain recovered APCs from diseased DO-KO mice present less of the MOG(35–55) epitope, (2) naïve DO-KO CD4 T cells have a more avid interaction with their own APCs, and (3) that hemagglutinin specific, DR1 restricted CD4 T cells had a less avid interaction with B cells from flu vaccinated DR1+DO-KO mice as compared to B cells from vaccinated DR1+DO-WT mice. These avidity changes could explain two things: (1) why we find that despite DR1+DO-KO mice have similar precursor levels of collagen specific CD4 T cells as DR1+DO-WT mice, they are more susceptible to the development of Collagen Induced Arthritis, even though we previously showed that the immunodominant collagen epitope is DM-sensitive. And, (2) why we find increased levels of regulatory T cells in the absence of DO.
Unconventional Endo-Lysosomal Assembly of Human Leukocyte Antigen B (HLA-B)
Authors: Olson Eli C , Raghavan Malini 
Published: February 2023

Abstract
The immune system surveys the body for foreign or mutated structures with the help of the human leukocyte antigen class I (HLA-I) protein complex, which displays protein fragments called peptides on the cell surface. The genes encoding the HLA-I heavy chain in humans are highly variable, which results in predisposition to or protection from diseases based on individual HLA-I variants. We have observed that sub-optimal assembly conditions for certain HLA-B variants produce peptide-deficient molecules on the cell surface. The monocyte immune cell type overcomes this deficiency in assembly, reversing the previously observed trends. Intracellular HLA-B accumulates in monocytes and monocyte-derived dendritic cells (moDCs) in endo-lysosomal compartments, a predicted location for supplemental peptide assembly. Current findings suggest that certain HLA-B variants are better able to efficiently assemble with intracellular and extracellular antigens in the endolysosomal compartments, conferring a selective advantage in infection conditions where traditional antigen presentation is blocked.
Roles of CX3CR1 and probiotic lactobacilli on the development of autoimmunity in MRL/lpr mice
Authors: Puig Xavier Cabana , Abdelhamid Leila , Swartwout Brianna , Zhu Jing , Liao Xiaofeng , Reilly Christopher M , Luo Xin M 
Published: February 2023

Abstract
Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with no known cure. Gut microbiota and the immune system have a close relationship that controls inflammation. Alterations in the gut microbiota, known as dysbiosis, can trigger SLE in both human and mouse. We previously published differences between the gut microbiota in lupus-prone MRL/Mp-Faslpr (lpr) mice compared to healthy controls, with lower Lactobacillaceae abundance in lpr mice. Restoring the gut microbiota with a mix of 5 different strains of this family significantly attenuated lupus-liked disease in lpr mice. In this study, we sought to understand the potential benefit of this mix in lpr mice with Cx3cr1 deficiency (KO). KO mice on C57BL/6 background display increased translocation of commensal bacteria into the mesenteric lymph node (MLN) and increased susceptibility to intestinal inflammation. However, whether CX3CR1+ macrophages play a role in controlling systemic inflammation was unclear. After backcrossing the KO allele to lpr mice, we found that KO lpr mice exhibited exacerbated splenomegaly and lymphadenopathy, as well as increased proteinuria. Interestingly, treating the KO lpr mice with the 5 Lactobacillus strains attenuated the enlargement of MLN and abrogated the increase of proteinuria. Furthermore, the effects of the probiotic bacteria were accompanied by downregulation of serum endotoxin, suggesting the reversal of a leaky gut that may explain their benefits on KO lpr mice. Together, our results show an important role of CX3CR1+ macrophages in controlling systemic inflammation in lupus, and that probiotic Lactobacillus spp. may be an effective treatment against SLE through preventing bacterial translocation.