bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoparticles Containing an Insulin-ChgA Hybrid Peptide Prevent Transfer of Type 1 Diabetes in NOD Mice by Expanding Foxp3+ Tregs
Authors: Jamison Braxton , Neef Tobias , Miller Stephen D. , Haskins Kathryn
Published: January 2023

In Type 1 Diabetes (T1D) autoreactive T cells destroy insulin-producing β-cells in the pancreatic islets. A major focus of our lab has been to identify novel peptide ligands for diabetogenic CD4 T cells isolated from non-obese diabetic (NOD) mice. We have identified a novel post-translational modification whereby a peptide from chromogranin A is covalently bound to a fragment from proinsulin, resulting in formation of a hybrid insulin peptide (2.5HIP) that is a potent ligand for the CD4 T cell clone BDC-2.5. Using an MHC class II tetramer to track the frequency and phenotype of endogenous 2.5HIP-reactive T cells in NOD mice, we found that these cells play a critical role in the disease process. The purpose of this project was to determine if poly(lactide-co-glycolide) (PLG) nanoparticles (NPs) loaded with 2.5HIP could be used to prevent induction of diabetes by transfer of BDC-2.5 TCR transgenic T cells cells into NOD.scid mice. We have found that i.v. infusion of 2.5HIP-coupled NPs (2.5HIP-PLG) one day after T cell transfer can almost completely prevent diabetes. Treatment with 2.5HIP-PLG leads to reduced T cell trafficking to the pancreas early on, as well as in vivo expansion of long-lived Foxp3+ regulatory T cells (Tregs) that express inhibitory receptors, membrane bound TGFβ-1/LAP, and stability markers. We predict that stable long-lived Tregs are critical for suppressing pathogenic IFN-γ producing T cells and maintaining long-term tolerance in this system. The end goal of this study is to determine if NPs containing HIPs can be used to prevent and/or reverse spontaneous disease in NOD mice. Results from these studies could have significant implications for the development of an antigen-specific therapy for T1D patients.
Extending remission and reversing new onset type 1 diabetes by targeted ablation of autoreactive T cells
Authors: Carroll Kaitlin , Elfers Eileen , Stevens Joseph , McNally Jonathan P. , Hildeman David , Jordan Michael Brian , Katz Jonathan D.
Published: January 2023

Preserving endogenous insulin production is clinically advantageous and remains a vital unmet challenge in the treatment and reversal of type 1 diabetes (T1D). While broad immunosuppression has had limited success in prolonging the so-called remission period, it comes at the cost of compromising beneficial immunity. Here, we employed an alternate strategy to specifically deplete the activated diabetogenic T cells that drive pathogenesis while preserving not only endogenous insulin production but also protective immunity. Effector T cells, such as diabetogenic T cells, are naturally poised on the edge of apoptosis because of activation-induced DNA damage that stresses the p53 regulation of cell cycle. We have found that the combined use of small molecular inhibitors that further potentiates p53 while inhibiting G2/M cell cycle checkpoint control drives apoptosis of activated T cells in vivo. When delivered at the onset of T1D these inhibitors eliminate diabetogenic effector T cells, prolong remission, preserve functional islets, and protect islet allografts while leaving naïve, memory, and regulatory T cell populations functionally untouched. Thus, the targeted manipulation of p53 and cell cycle checkpoints represents a new therapeutic modality for the preservation of islet beta cells in new onset type 1 diabetes or after islet transplant.
ALLERGIC LUNG INFLAMMATION IN OFFSPRING OF PREGNANT MICE EXPOSED TO ORGANIC DUST
Authors: Nascimento Amanda AN , Schneberger David , Kirychuk Shelley , Pandher Upkar , Thompson Brooke , Singh Baljit
Published: January 2023

The hygiene hypothesis shows that there is a strong correlation between microbial exposures in early life and the absence of allergies and asthma. However, studies also show that these same microbial exposures in early life can cause psychiatric and behavioral problems. Lipopolysaccharide (LPS), originating from microbes, is ubiquitous in animal holding facilities such as pig barns. The influence of CD34, an adhesion protein important in development of lung inflammation, in the association between microbial exposures and asthma, are not known, nor is the association between CD34 and behavior. We studied pulmonary immune responses and behavior of male and female offspring of wild-type and CD34−/− pregnant mice exposed to pig barn air for 4 hours/day for 5 days/week for 21 period of pregnancy. The ovalbumin protocol was used to induce asthmatic responses in the offspring. All OVA-treated CD34−/− and WT mice had more AhR, leukocytes and IL-4, IL-5, IL-6, and IL-13 compared to their respective controls (P<0.05) showing development of asthmatic response. All CD34−/− asthmatic as a group had lower AhR, total leukocytes and levels of IL-4, IL-5, IL-6, and IL-13 compared to WT asthmatic mice. However, CD34−/− and WT asthmatic females compared to CD34−/− and WT males asthmatic mice had higher AhR, total leukocytes and cytokine levels. Also, in the general activity in open field the asthmatic females had lower locomotion (P < 0.05) compared to the male asthmatic mice These data show that female offspring of those exposed to LPS-contaminated environment had higher degree of asthmatic lung responses and behavioral changes compared to the males affect females more frequently than males
FLX193: A Potent, Selective CCR4 Antagonist for Allergic Disorders
Authors: Jorapur Aparna , Marshall Lisa , Bradford Delia , Brovarney Martin , Chian David , Wadsworth Angela , Sanchez Jerick , Jacobson Scott , Karbarz Emily , Robles Omar , Younai Ashkaan , Ketcham John , Ng Andrew , Tivitmahaisoon Parcharee , Pookot Deepa , Marubayashi Sachie , Kozon Nathan , Colas Christophe , Okal Abood , Cutler Gene , Wustrow David , Schwarz Jacob , Talay Oezcan , Brockstedt Dirk , Wong Brian
Published: January 2023

Type 2 helper T cells (Th2)cells have been shown to express CCR4 receptor, and play a critical role in driving the pathogenesis of asthma and atopic dermatitis. FLX193 is a best-in-class, highly-potent and selective small molecule CCR4 antagonist under investigation for the treatment of allergic disorders. FLX193 blocked migration of CCR4+ Th2 cells (human and mouse) towards CCL17 and CCL22 in an in vitro chemotaxis assay. FLX193 is well-tolerated in animals at efficacious doses. In an Ovalbumin (OVA)-induced asthma model, FLX193 significantly reduced lymphocyte and eosinophil counts in the Bronchoalveolar lavage (BAL) fluid and showed a reduction of the effector Th2-relevant cytokines IL-5 and IL-13. FLX193 treatment also reduced the levels of CCL17 and CCL22 in the BAL fluid, indicating an overall reduction of inflammation. In addition, we used an atopic dermatitis mouse model to demonstrate that treatment with FLX193 decreased CCR4+ T-cell mediated inflammation. Hence, FLX193 shows promise in the treatment of atopic dermatitis.
Anti-CD4 autoantibody-mediated failure of CD4+ T cell reconstitution in HIV-infected patients under viral-suppressive ART
Authors: Jiang Wei , Luo Zhenwu
Published: January 2023

Increased mortality and morbidity occur in HIV-infected patients who fail to increase CD4+ T cell counts under viral-suppressive antiretroviral therapy (ART). Here we identified an underlying mechanism. Plasma anti-CD4 IgGs were measured by ELISA in 17 healthy controls, 26 HIV+ immunologic responders (IR, aviremic, CD4+ T cell counts ≥ 500 cells/μL), and 22 non-responders (NR, aviremic, CD4+ T cell counts < 350 cells/μL). Anti-CD4 IgGs were purified from plasma of 21 NR by affinity purification. Antibody-dependent cytotoxicity (ADCC) was performed in CD4+ T cells co-cultured with NK cells in presence of anti-CD4 IgGs or control IgGs in vitro. Plasma microbiome was analyzed by bacterial 16S DNA sequencing. Elevated plasma levels of anti-CD4 IgGs were found in NR [median (interquartile range, ng/mL), 92 (53–166)] compared to IR [26 (16–82)] and healthy controls [16 ng/mL (9–24)] (P < 0.001 between NR and two controls, ANOVA). Higher plasma level of anti-CD4 IgG correlated with blunted CD4+ T cell recovery (r = −0.53, P = 0.0002, Spearman correlation test). Furthermore, purified anti-CD4 IgGs induced NK cell-dependent CD4+ T cell cytolysis (P = 0.02). Notably, Simpson diversity was lower in patients with plasma anti-CD4 IgG ≥ 50 ng/mL compared to patients with anti-CD4 IgG < 50 ng/mL (P = 0.04). There was an inverse correlation between plasma anti-CD4 IgG and the Simpson diversity index in patients (r = −0.47, P = 0.03) but not in healthy controls. These results indicate a possible link between microbiome and B cell dysfunction in HIV, and anti-CD4 IgGs may play an important role in preventing CD4+ T cell reconstitution despite viral-suppressive ART.
PET imaging of TSPO in a rat model of sepsis induced by peritoneal polymicrobial infection
Authors: Barichello Tatiana , Giridharan Vijayasree V , Petronilho Fabricia , Generoso Jaqueline S , Dominguini Diogo , Dal-Pizzol Felipe
Published: January 2023

Background

Sepsis is a life-threatening acute organ dysfunction secondary to infection that affects more than 30 million people worldwide. In the USA, 1.5 million people develop sepsis, and at least 250,000 Americans die from sepsis each year. After hospitalization, patients suffer from long-term impairments in memory, attention, verbal fluency, and executive functioning. The translocator protein (TSPO), marker of activated microglia astrocytes cells, can be measured in vivo using positron emission tomography (PET). Our working hypothesis is that systemic inflammation associated with sepsis activate microglia cells, which will later lead to further long-term cognitive impairment in sepsis survivors.

Methods

To test this hypothesis, adult male Wistar rats were subjected to a gold standard sepsis model induced by cecal ligation and perforation (CLP) surgery to induce peritoneal poly microbial sepsis or sham surgery as a control group. At 24 hour after the surgery the animals were subjected to translocator protein (TSPO) microPET imaging with [11C]PBR28. Following the imaging, TSPO, cytochrome C, cytokines/chemokines, microglia (Iba-1) and astrocyte marker (GFAP) were measured in the prefrontal cortex and hippocampus of the septic animals.

Results

septic animals presented and increased uptake of [11C]PBR28-microglia activation in the whole brain compared to control at 24 after the CLP surgery. The expression of IL-1α, IL-1β, IL-6, IL-18, TNF-α, IFN-γ and Iba-1 increased in the hippocampus of septic rat.

Conclusion

The upregulation of TSPO expression in the hippocampus of septic rat brain is a possible mechanism associated with long-term cognitive impairment in sepsis survivors.
High T cell percentage predicts improved overall survival in de novo Acute Myeloid Leukemia
Authors: Saultz Jennifer N , Wang Weiwei , Lind Evan F , Kaempf Andy , Fan Guang , Mori Tomi , Park Byung
Published: January 2023

Intro

Acute myeloid leukemia (AML) is associated with defects in innate and adaptive immunity leading to immune evasion and leukemia survival. Given the important connection between the immune system and AML, our group sought to understand the prognostic significance of immune subsets in the bone marrow.

Methods

Patient samples were obtained from the Oregon Health and Science University (OHSU) pathology department between September 2010 and March 2016. This cohort study includes 82 newly diagnosed adult AML patients who had a bone marrow biopsy that was subjected to flow cytometry and a targeted-NGS panel.

Results

This retrospective cohort of 82 newly diagnosed AML patients was 53.7% male with a median age of 61 years (range 18 – 83). Using 2017 ELN risk guidelines, 40% of patients were classified as favorable, 24% as intermediate, and 35% as adverse. The percent T cells of lymphocytes ranged from 41.0 to 90.9 (median 72.5). The percent of NK cells ranged from 2.1 to 22.6 (median 8.7). Separate Cox regression models were applied to each immune cell group in both the univariable and multivariable settings, with the latter models accounting for patient age and ELN risk. Higher T cell percentages were correlated with longer survival, even when adjusting for age and ELN risk (p=0.024; HR=0.87 [95% CI: 0.78 – 0.98] for each 5-unit increase). Conversely, in the absence of other patient features, higher NK cell percentages were predictive of worse OS (p=0.015).

Conclusions

In this study, we show that higher T cell percentages at diagnosis are associated with improved OS. This association is most evident in patients at least 60 years old or those with intermediate ELN risk.
Identification of autophagy markers in clinical cases of sepsis
Authors: Madiraju Charitha , Mallarpu Chandra Shekar , Prasad Sudhir , Singarapu Maneendra , Brar Harvinder , Bratic Nemanja , Haririparsa Neda , Kim Jean H. , Ponnana Meenakshi , Chelluri Lakshmi Kiran
Published: January 2023

Apoptotic cell death plays a key role in sepsis-induced immunosuppression and organ dysfunction. Autophagy may serve as a compensatory protective mechanism in sepsis owing to its potential role in reversing cell death-induced immunosuppression. The goal of our study was to investigate for the presence of autophagy markers in septic patients. Our preliminary study design included patients diagnosed with, and treated for, sepsis in clinical settings (N =13). Healthy volunteers served as control subjects (N = 10). Markers of autophagy were assessed in serum, peripheral blood mononuclear cells (PBMCs) and PBMC lysates derived from patients and healthy controls. Samples were analyzed by ELISA and flow cytometry methods. Data and statistical analyses were performed using GraphPad Prism v7.0. Results from flow cytometry analysis showed significantly elevated levels of autophagy markers in PBMCs derived from septic patients compared to that observed in PBMCs from control subjects (p < 0.01 from unpaired t-test analysis). Results from ELISA experiments showed significantly lower levels of the autophagy marker in patient serum samples when compared to that seen in control serum samples (p < 0.01 from unpaired t-test analysis). ELISA analysis showed a concomitant increase in the same autophagy marker in PBMC lysates obtained from patients with sepsis compared to that observed in PBMC lysates from control subjects. Preliminary results serve as a basis for us to investigate the role of autophagy in the prediction of clinical outcomes in sepsis.
URT bacterial microbiota interacted with H1N1 infection by IL-1 pathway in C57BL/6
Authors: li heng , Wu Qiongwen , Guo Lei , Li Nan , Zheng Huiwen , Li Hongzhe , Yang Zening , Huang Xing , Yang Jinxi , Chu Manman , Liu Longding
Published: January 2023

The bacterial microbiota correlated with the inflammatory response, and inflammations are developed with high frequency when infections happened in the upper respiratory tract (URT). However, it has rarely been studied that the mechanisms in the interaction between the bacterial microbiota and the infections appeared in URT. In our subjects, we researched the interaction between H1N1 infection and URT bacterial microbiota by IL-1 pathway in C57BL/6. We extracted the DNA in URT and performed 16S rRNA amplicon sequencing. When IL1 gene was knocked out, Streptococcus, Bergeyella and Enterococcus increased as major parts in the bacterial microbiota, and Staphylococcus, Rothia and Atopostipes decreased noticely. And then, the wild type mice and IL1−/− mice were infected by H1N1 in 1500TCID50, and the samples on Day1, Day3 and Day7 were collected to detect the URT bacterial microbiota. We found that these bacterias correlated with IL1 maybe play important roles in H1N1 infection. We validated the increase of streptococcus pneumoniae, Bergeyella zoohelcum and Enterococcus faecalis, and the decrease of Staphylococcus lentus and staphylococcus aureusby real time PCR. The RDA analysis and regression analysis showed that the virus load of H1N1 in URT correlated with the bacterial microbiota composition noticeably. The detection of the IgG, IgA and memory B cells showed that there were simmilar trends in wild type mice and IL1−/− mice, and the level of memory B cells in wild type mice were more. We analysized comprehensively the results above, and indicated that the clear correlation between the bacterias in URT and the H1N1 infection, maybe the URT bacterial microbiota could play roles in the immune system to response to the H1N1 infection.
Resistin immunomodulation in healthy and septic patients
Authors: Li Jiang , Bonenfant Jeffrey , Nasouf Luqman , Miller Joseph , Mittal Aarti , Klein Walter , Nair Meera G
Published: January 2023

Sepsis is a major healthcare challenge worldwide with no effective therapies. Sepsis pathogenesis involves immune dysregulation, however, the underlying mechanisms of inflammation that are protective or pathogenic in sepsis remain unclear. Human resistin is an immune cell-derived protein that is elevated in sepsis. Employing human resistin-expressing transgenic mouse we identified a protective role for resistin in preventing fatal LPS endotoxic shock. Resistin binds to the LPS receptor, Toll-like receptor 4, through its N-terminal helix and triggers a switch from pro-inflammatory to anti-inflammatory responses. We hypothesize that resistin is a novel therapeutic for sepsis. We generated recombinant resistin and resistin N-terminal helices and tested their anti-inflammatory function in peripheral blood mononuclear cells (PBMC). Resistin, or its N-terminal helix alone, inhibited LPS-induced TNFa secretion by PBMC from healthy donors, but this inhibitory activity was abrogated without the helical structure. Next, we recruited 46 septic patients; 52% infection with LPS-rich gram-negative bacteria, and 30% mortality. Preliminary analysis revealed that circulating resistin was significantly higher in all septic patients compared to healthy donors, but that there were three distinct groups in the septic samples: high, medium and low resistin expression. Flow cytometry analysis revealed striking changes in immune cell subsets including monocytes, neutrophils, T cells and natural killer cells. Ongoing studies are investigating the immunomodulatory potential of resistin and its N-terminal helix in septic samples and associations with the infectious pathogen, circulating cytokines and immune cell subsets.
HIV infection drives immune activation of angiogenic T cells
Authors: Tong Li , Schmidt Marcel , Zhu Ziang , Chen Jinya , Wellstein Anton , Kumar Jai , Kumar Princy , Catalfamo Marta
Published: January 2023

In patients with HIV infection, chronic immune activation, systemic inflammation and endothelial dysfunction have been identified as the main drivers of cardiovascular risk/disease. In addition, recent reports have shown that, T cells with angiogenic properties (Tang) contribute to vascular repair by promoting new vessels formation in vivo and in vitro. In the present study, we hypothesized that HIV drives immune activation of Tang cells. We measured the frequency and phenotype of circulating Tang cells defined as CXCR4+CD31+. Patients with HIV infection and well controlled viral replication by cART (n= 25) showed a decreased proportion of both CD4 and CD8 Tangs cells when compared to healthy controls (n= 12), although this difference was more striking in the CD8 Tang subset. CD8 Tang but not CD4 Tang cells were significantly decreased in HIV negative patients whom are undergoing PrEP (Pre-Exposure Prophylaxis) therapy, (n=5). In addition, we found that: angiogenic T cells as defined by the surface markers CXCR4 and CD31 are a heterogenous population including naïve, memory and terminal effector memory phenotypes. Tang cells of HIV infected patients showed an activated phenotype with increased expression of granzymes A (GZA) and B (GZB) when compared to healthy controls. Lastly, CD4 and CD8 Tang cells show increased expression of CD49f (integrin a-6). The frequency of Tang GZA+GZB+ in patients with HIV infection was positively associated with 10yr cardiovascular risk score (ASCVD), CD4 Tang (R= 0.51, p= 0.02) and CD8 Tang (R= 0.6, p< 0.01). These results suggest that in the context of HIV infection, angiogenic T cells possess an immune activated phenotype with a proinflammatory potential that may alter their ability of vascular repair
Endoplasmic reticulum stress regulates immunosuppressive function of myeloid derived suppressor cells in leprosy
Authors: Kelly-Scumpia Kindra , Shirazi Roksana , Modlin Robert
Published: January 2023

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells defined by their phenotype along with the ability to suppress adaptive T cell responses. Although MDSC are expanded in response to microbial infection, the factors that regulate the suppressive function of MDSC in this context are not known. Here, we studied MDSC in patients with leprosy, a chronic infectious disease caused by Mycobacterium leprae, in which the clinical manifestations including bacterial load present on a spectrum that correlates with the type of immune response. We found cells with a granulocytic MDSC phenotype are increased in patients across the spectrum of leprosy. However, only MDSC from leprosy patients with disseminated multibacillary infection, not patients with localized paucibacillary disease or healthy controls, suppress M. leprae- specific T cell proliferation and IFN-γ production. An increase in an ER stress gene signature was seen in MDSC from multibacillary patients vs paucibacillary patients. Additionally, the immunosuppressive function of MDSC from multibacillary patients was reversed by either treatment with a free radical scavenger or blockade of interleukin (IL)-10. Conversely, induction of ER stress in MDSC-like cells from paucibacillary patients was sufficient to induce suppressor activity. These studies of human leprosy link multibacillary infection, ER stress and MDSC suppressive function.
Commensal microbiota as possible pathobiont in autoinflammatory disease
Authors: Siak Jay , St. Leger Anthony , Raychaudhuri Kumarkrishna , Mattapallil Mary , Fuss Ivan J , Goldbach-Mansky Raphaela , Strober Warren , Caspi Rachel R
Published: January 2023

The ocular surface has an associated microbiome that contributes to maintenance of local immune homeostasis and protects the ocular surface from fungal and bacterial infections. However, in individuals with a dysregulated immune response, commensal flora could cause pathology. In this study, we seek to understand how an ocular commensal colonizing humans and mice, C. mastitidis (C. mast), stimulates immunity in the immunologically perturbed host. Cryopyrin Associated Periodic Syndrome (CAPS) patients suffer from systemic and ocular autoinflammatory disease caused by a hyperactive NLRP3 inflammasome. Knock-in mice bearing a mutated NLRP3 gene cloned from a CAPS patient responded to ocular colonization with C. mast by increased conjunctival neutrophilia, which progressed to overt ocular surface disease. Compared to wild type (WT) controls, their BM dendritic cells produced elevated IL-1 in response to C. mast. Additionally, gd T cells, which were primarily the Vg4 subset, isolated from eye-draining lymph nodes of C. mast-associated mutant mice were more activated and produced more IL-17, suggesting a qualitatively analogous but quantitatively amplified response compared to WT. Importantly, the same commensal elicited strongly elevated IL-17 production from leukocytes of inflammasome disease patients when compared with healthy controls. Our results suggest that C. mast induces an abnormal immune response in the NLRP3 mutant and acts as a pathobiont, in contrast to its behavior in the immunologically normal host. Based on these data, we hypothesize that the recurrent non-infectious conjunctivitis observed in CAPS patients may be driven by a hyperactive immune response to their own ocular surface bacteria.
Modulation of respiratory syncytial virus-induced epithelial proinflammatory mediator HMGB1 via activation of histone deacetylase
Authors: Kempaiah Kempaiah Rayavara , Kurosky Alexander , Hosakote Yashoda Madaiah
Published: January 2023

Respiratory syncytial virus (RSV) is the leading cause of serious respiratory illness in children and a major cause of severe respiratory morbidity and mortality in the elderly, for which no effective treatment or vaccine is currently available. High Mobility Group Box-1 (HMGB1) is a redox-sensitive multifunctional nuclear protein that translocates to the cytoplasm and subsequently released to the extracellular space during infection and injury, and regulates immune and inflammatory responses as a damage-associated molecular pattern. Our studies show that RSV-induced oxidative stress hyperacetylates, phosphorylates and oxidizes HMGB1 to promote its extracellular release and that secreted HMGB1 triggers inflammatory responses by activating innate immune cells to promote inflammation. The goal of this study was to investigate the effect of histone deacetylases HDAC1 and sirtuin 1 (SIRT1) activation on RSV-induced epithelial HMGB1 extracellular release and its proinflammatory function. Studies were conducted in airway epithelial cells, a human lung carcinoma cell line and normal small alveolar epithelial cells. Cells were transfected with HDAC1 and SIRT1 siRNA followed by infection with RSV and determined HMGB1 levels by Western blot, ELISA and RT-PCR. Our studies demonstrated that inhibition of deacetylase activity enhanced RSV-induced HMGB1 secretion due to increased acetylation of HMGB1, which promotes inflammation. Activation of deacetylases using resveratrol significantly inhibited RSV-induced HMGB1 release. These studies will lead to the modulation of the RSV-induced epithelial HMGB1 proinflammatory function, which may pave the way for the development of novel therapeutic interventions for RSV infections.
Skin transcriptomics reveals novel insights into pathophysiological mechanisms in humanized mice models of Group A Streptococcal Necrotizing Soft Tissue Infections
Authors: Nookala Suba , mukundan Santhosh , Scheidegger Adam , Ambigapathy Ganesh , Combs Colin , Kotb Malak
Published: January 2023

Despite prompt surgical debridement, clindamycin treatment with adjunct intravenous immunoglobulin and hyperbaric oxygen therapies, Necrotizing Soft Tissue Infections (NSTI) caused by Group A Streptococcus (GAS) bacteria progress rapidly into deeper layers of tissues, fascia, or muscle, portending significant morbidity and mortality. Our previous findings strongly support a role for host genetic factors, specifically, polymorphisms in HLA-Class II alleles in driving differential disease severity and NSTI outcomes. To facilitate a better understanding of pathophysiological mechanisms underlying NSTI, this study used a combined network and pathway analysis of the transcriptome data of GAS infected skin lesions from transgenic mice expressing human HLA-II alleles associated with varying susceptibility to NSTI. Our data analysis not only reaffirmed known modulators of NSTI susceptibility but revealed novel transcription factors and signaling pathways unique to immune functions. From these data we predict potential mechanisms by which GAS adapts in previously unidentified host niches. Our findings also provide new insights into the consequences of these extreme adaptations of GAS in the host during NSTI.
Macrophage-associated lipin-1 enzymatic activity promotes inflammation in vitro and in vivo
Authors: Vozenilek Aimee E , Woolard Matthew D
Published: January 2023

During atherosclerotic progression, macrophage lipid handling dictates macrophage responses. As macrophages process modified low-density lipoproteins (modLDLs), glycerolipid synthesis is turned on to process lipids into storage sites for excess cholesterol. The key regulatory enzyme in this pathway is lipin-1, a phosphatidic acid phosphohydrolase. In vitro studies provide evidence that lipin-1 enzymatic activity initiates a PKCα/βII-ERK1/2-cJun signaling cascade that primes the macrophage to be hyper-responsive to subsequent pro-inflammatory stimulus. Our in vivo data demonstrated that mice lacking lipin-1 enzymatic activity in myeloid-derived cells (lipin-1mEnzyKO) had decreased atherosclerosis. However, it is currently unknown if the loss of lipin-1 and as a result the decreased inflammatory response is responsible for the decreased severity of atherosclerosis observed in our lipin-1mEnzyKO mouse model. We defined the transcriptome regulated by lipin-1 within modLDL/lipopolysaccharide stimulated wild-type and lipin-1mEnzyKO macrophages. The loss of lipin-1 led to a reduction of pro-inflammatory transcripts. To link the decrease in inflammation in the lipin-1mEnzyKO BMDMs with the decrease in atherosclerosis severity seen in vivo, we collected RNA from the aortic arch of lipin-1mEnzyKO and wild-type mice. Analysis of the RNA using an Atherosclerosis RT2 Profiler Array indicated that the lipin-1mEnzyKO mice showed increases in anti-apoptotic gene transcripts and decreases in transcripts related to extracellular matrix degradation suggesting lipin-1mEnzyKO mice may have more stable plaques.
Loss of testosterone impairs anti-tumor neutrophil function
Authors: Markman Janet , Wakita Daiko , Porritt Rebecca A. , Posadas Edwin , Crother Timothy R. , Arditi Moshe
Published: January 2023

In men, the incidence of melanoma rises rapidly after age 50, and nearly two thirds of melanoma deaths are male. The immune system is known to play a key role in controlling the growth and spread of malignancies, but whether age- and sex-dependent changes in immune cell function account for this effect remains unknown.

Methods

We used B16 and YUMM melanoma lung metastatic models. Neutrophil depletion, castration, testosterone (T) replacement, and bone marrow transplant (BMT) were performed. Neutrophils from prostate cancer patients were analyzed.

Data

In castrated male mice, neutrophil maturation and function are impaired, leading to elevated metastatic burden in two models of melanoma. Remarkably, replacement of T effectively normalized the tumor burden in castrated male mice. Neutrophil depletion increased tumor burden only in males, suggesting a sex difference in neutrophils. Sex BMT experiments showed that the hormonal microenvironment is crucial, not the sex of the immune cell. Further, a BMT from ARTfm mice with a truncated androgen receptor increased tumor burden and impacted neutrophil function towards a pro-tumor phenotype. Finally, the aberrant neutrophil phenotype was also observed in prostate cancer patients receiving androgen deprivation therapy, highlighting the evolutionary conservation and clinical relevance of the phenotype.

Conclusion

Our data indicate that innate immunity is important for the response against melanoma colonization and suggest a sex specific response of neutrophils with impaired function in the absence of T. Taken together, these results provide a better understanding of the role of androgen signaling in neutrophil function and the impact of this biology on immune control of malignancies.
IL-15 Activates Liver Sinusoidal Mucosal-associated Invariant T Cells to Exert TCR/MR1-independent Innate-like Cytotoxicity
Authors: Rha Min-Seok , Han Ji Won , Kim Jong Hoon , Koh June-Young , Park Hye Jung , Kim Soon Il , Kim Myoung Soo , Lee Jae Geun , Park Jun Yong , Park Su-Hyung , Joo Dong Jin , Shin Eui-Cheol
Published: January 2023

Mucosal-associated invariant T (MAIT) cells are the most dominant population of innate-like T cells in the human liver and predominantly localized in liver sinusoids. MAIT cells can be activated by MR1-dependent TCR stimulation or cytokines such as IL-12 and IL-18. However, effects of IL-15 on MAIT cells have not been comprehensively studied, particularly in the aspect of their innate-like cytotoxic activity. In the present study, we examined effects of IL-15 on liver sinusoidal MAIT cells obtained from donor liver perfusates during liver transplantation. IL-15 activated MAIT cells to have a cytotoxic phenotype and induces cellular proliferation. Moreover, IL-15-activated liver sinusoidal MAIT cells exerted innate-like cytotoxicity that is independent of TCR and MR1. Increased target cell conjugation and NKG2D-dependent stimulation were responsible for innate-like cytotoxicity of IL-15-activated MAIT cells, and PI3K–mTOR pathway was critically required for IL-15-induced innate-like cytotoxicity. Furthermore, we observed an increased NKG2D expression in intrahepatic MAIT cells from patients with acute hepatitis A, in which liver injury is known to be mediated by IL-15-induced innate-like cytotoxicity of T cells (Immunity 2018, 48:161). In summary, our data demonstrate IL-15 activates liver sinusoidal MAIT cells to exert TCR/MR1-independent cytotoxicity, and suggest a potential role of liver sinusoidal MAIT cells in immune responses or immunopathogenesis in liver diseases.
Clonal selection of cross-reactive memory B cells dominates recall responses against heterologous flaviviruses without a requirement for secondary affinity maturation
Authors: Wong Rachel , Richner Justin , Zhao Haiyan , Shlomchik Mark J , Diamond Michael S , Bhattacharya Deepta
Published: January 2023

Members of the flaviviridae family include a number of globally relevant pathogens such as West Nile (WNV), Japanese Encephalitis (JEV), Dengue, and Zika viruses. Upon clearance of a primary flavivirus infection, both neutralizing and non-neutralizing antibody specificities are generated and maintained. These antibodies can play protective or pathogenic roles after subsequent infection with heterologous flaviviruses. To define the cells capable of responding to secondary heterologous infections, we utilized a WNV and subsequent JEV vaccination model. Using tetramer reagents directed at the potently neutralizing lateral ridge epitope on envelope protein domain III (DIII) of WNV. We found that memory B cells were more antigenically diverse and cross-reactive than were long-lived plasma cells. To determine how this memory B cell diversity is generated and subsequently utilized, we generated a mouse model in which deletion of activation induced cytidine deaminase (AID) is temporally driven by hCD20-CreERT2. Deleting AID during ongoing germinal center reactions against WNV did not affect the antigen specificity or quantity of memory B cells or bone marrow plasma cells. Deletion of AID during the memory phase following WNV vaccination did not alter the cellular response to JEV compared to wild type mice. Thus, cross-reactive B cells selectively enter the memory B cell compartment and are excluded from the long-lived plasma cell compartment through a B cell receptor affinity maturation-independent mechanism. Analysis of germline-reverted monoclonal antibodies derived from DIII-specific memory B cells and long-lived plasma cells suggests that the fate of a B cell is imprinted at the naive state.
B cell anergy: Atheroprotective, yet vulnerable to atherosclerotic conditions
Authors: Waseem Tayab , Keeter William Coles , Moriarty Alina , Edemobi Stefan , Pham Michael , Getahun Andrew , Cambier John C , Galkina Elena
Published: January 2023

Anergy is the major mechanism for peripheral tolerance. Recent reports highlight the role of B cell anergy in lupus, type 1 diabetes, and arthritis, but little is known about the induction and maintenance of anergic B cells within atherosclerosis. ARS/A1 mice have B cells that respond with moderate affinity to Ars hapten, but also cross-react with low affinity to endogenous ssDNA resulting in an anergic B cell repertoire. To explore the role of B cell anergy in atherosclerosis, we examine ARS/A1 and BL/6 littermate controls that have been fed a western diet for 16 weeks and injected with AAV-PCSK9 to induce atherosclerosis. Our data showed that ARS/A1 mice had 44% less lesions, and a decreased inflammatory profile compared to BL/6 controls. The role of B cells in atherosclerosis varies by B cell subsets. Whereas marginal zone B cells (MZ) are atheroprotective, follicular B cells (FO) accelerate atherosclerosis. To further explore how an atherosclerotic environment affects B cell subsets, we compared the percentages of splenic B cell subtypes in PCSK9-treated vs healthy ARS/A1 controls. Our data showed a significant decrease in ARS/A1 FO B cells and an increase in ARS/A1 MZ B cells suggesting a skewing of B cell subsets upon exposure to atherosclerotic conditions in ARS/A1 mice. Surprisingly, we detected an increased calcium response upon BCR crosslinking and increase levels of CD86 in B cells from PCSKS-9-injected ARS/A1 vs BL/6 controls. Overall, our data suggests that while anergy is atheroprotective, the inflammatory environment seen within atherosclerosis may prime B cells to increase the responsiveness of anergic B cells to activation.
Discovery of perforin-expressing killer B cells in vertebrates
Authors: Sunyer J. Oriol , Shibasaki Yasuhiro , Takizawa Fumio , Gonzalez Michael , Boudinot Pierre
Published: January 2023

Our previous work has shown the existence of distinct subsets of B cells in vertebrates that are highly phagocytic. To understand further the involvement of B cells in other potential innate immune functions, we performed the first comparative transcriptome analysis on FACS-sorted IgT+ and IgM+ B cells in rainbow trout, a primitive teleost fish species. To our surprise the gene that showed the highest differential expression between these two B cell subsets was perforin, a molecule that is not typically associated with B cells. The results obtained by transcriptome were expanded by further RT-PCR analysis confirming that unlike IgM+ B cells, IgT+ B cells expressed high transcript levels of several perforin isoforms, including, prf1-like-B, prf1-like-C and prf1-like-D. We also confirmed the unique expression of these perforin genes in IgT+ B cell by single cell transcriptome analysis. Moreover, we produced antibodies against these perforin molecules and demonstrated by immunohistochemistry the presence of several of these perforin isoforms in IgT+ B cells. Since perforin is a cytolytic protein we hypothesized that IgT+ B cells could possess cytotoxic activity similar to that of other perforin-expressing cells. To confirm this hypothesis, we tested the potential cytotoxic capacity of IgT+ B cells towards several mammalian cell lines, such as HL-60. Our results show that the killing activity of IgT+ B cells was significantly greater than that of IgM+ B cells. As IgT+ B cells and the IgT antibodies they produce play key roles in fish mucosal surfaces, our results strongly suggest a cytotoxic role for mucosal B cells in these species. Overall, our findings demonstrate a previously unrecognized new function for vertebrate B cells in immunity.
How TLR9 Signaling shapes the survival, differentiation and the metabolism of B cells
Authors: Akkaya Munir , Akkaya Billur , Theall Brandon , Traba Javier , Pena Mirna , Pierce Susan K
Published: January 2023

The signaling cascades initiated by binding of the antigen to B cell receptor (BCR) leads to rapid increases in cellular respiration, nutrient uptake and expression of various activation markers. However, unless a second, independent stimulus is received soon after antigen binding, BCR signaling does not lead to B cell proliferation and differentiation. Instead, BCR signaling alone leads to a dysregulation of cellular calcium homeostasis which in turn causes mitochondrial dysfunction and a phenomenon called activation induced cell death. The second signal can be provided by Toll like receptor (TLR) signaling, indicating the presence of an acute infection or through B cell-T cell interactions that rules out that the initial antigen was a prohibited self-antigen. Additionally, there is an interplay between TLR versus T cell mediated second signals, namely that TLR signaling trumped the need for the antigen-stimulated B cell to interact with T cells to receive a ‘go’ signal. TLR stimulation decreased B cells’ ability to capture, process and present antigens to solicit help from T cells. Rather TLRs directly boosted B cell antibody and cytokine secretion and proliferation. Thus, TLR signals drive B cells toward rapid T cell-independent differentiation to plasma cells providing rapid neutralizing antibody production to fight off infections quickly. In contrast B cells that receive their survival signals from T cells are induced to undergo a time-consuming process that is necessary for antibody affinity maturation and long-lasting immune memory. Therefore, the TLR driven shortcut to quick antibody comes with a price which is the absence of “crème de la crème” antibodies that would protect the body from subsequent infections for years to come.
Interleukin-27-producing B cells are critical regulators of immunity during persistent viral infection
Authors: Pratumchai Isaraphorn , Huang Zhe , Zak Jaroslav , Teijaro John R
Published: January 2023

B cells regulate immune responses by both generating antibodies and through cell surface interactions and cytokine production that provide signals to various cells to modulate humoral and cell-mediated immunity. During persistent viral infection, IL-27R is required for viral control which correlates with impaired anti-viral CD4+ T cell responses and lower LCMV-specific antibody production. Here, using mice with conditional B cell–specific IL-27 p28 deletion, we identify IL-27-producing B cells as key players in promoting control of persistent viral infection. Mice in which B cells lacked IL-27 p28 expression lost the ability to control persistent LCMV infection. The impaired immunity was associated with the reduction of GC B cells, plasma cells and Tfh cells. In addition, these mice also displayed reduced virus-specific CD8 T cells and lost the ability to expand CXCR5+ follicular CD8 T cells following anti-IFNAR1 treatment, suggesting that B-cell-derived IL-27 p28 regulates immunity by providing signals to T cells. To assess the role of IL-27 signaling in T cells we generated IL-27R conditional KO mice by mating IL-27Ra-floxed mice with CD4 and Granzyme B-Cre strains. Mice in which IL-27Ra was conditionally ablated in all T cells lost the ability to control persistent LCMV infection. In addition, these mice produced significantly lower titers of virus-specific IgG2a throughout the course of infection despite similar levels of virus-specific IgG1. Finally, we identify plasma cells expressing the transcription factor Blimp1 as a major source of IL-27 p28 during persistent LCMV infection. Overall, our study highlights the importance of IL-27-producing B cells in regulating T cell responses and control of persistent viral infection.
Distinct Antibody Repertoire of Cerebral Spinal Fluid B Cells from Healthy Controls
Authors: Husain-Krautter Sehba , Vos Duncan , Gallego Juan A , Malhotra Anil K , Rothstein Thomas L
Published: January 2023

Antibodies have been implicated in the pathogenesis of several neuropsychiatric diseases. Although these disease-associated antibodies typically circulate (eg, Sydenham’s Chorea), they can arise from autoreactive B cells in situ, located within the central nervous system itself (eg, Multiple Sclerosis). Although normal human cerebral spinal fluid (CSF) has been classically considered to be acellular, the presence of B cells in CSF from healthy controls has been reported (Ho et al. 2013, Kleine 2015). In order to provide context in elucidating the pathophysiology of autoreactive B cells in disease, we questioned the origin of CSF B cells in healthy donors. Specifically, we asked whether CSF B cells represent a distinct population (select subset), or a random assortment, of peripheral B cells in the same individual. We obtained paired samples of CSF and peripheral blood (PB) from 4 healthy control volunteers. B cells were isolated by immunofluorescent staining and cell sorting, followed by immunoglobulin amplification and sequencing. We confirmed that each normal CSF sample contained small numbers of B cells. We found highly significant differences in V-D-J usage of immunoglobulin from these B cells as compared to V-D-J usage of matched PB B cells, with significance determined by Chi-square goodness of fit, confirmed by resampling-based permutation tests. These results indicate that B cells are selected for entry into, or persistence in, the central nervous system, and are not simply a random reflection of B cells circulating at any given time. This suggests the value of examining the repertoire of CSF B cells that may be pathogenic agents in neuropsychiatric diseases whose origin remains obscure, such as schizophrenia.
The role of innate immune cells in Contact Hypersensitivity
Authors: On Kathy , Tikoo Shweta , Jain Rohit , Weninger Wolfgang
Published: January 2023

Background

Contact hypersensitivity (CHS) is a murine model used to investigate the role of the immune system in eliciting the skin’s inflammatory response to small compounds called haptens. Although many studies have identified the immune cell subsets involved in mediating the inflammatory response, the spatiotemporal behaviour of these immune cells in vivo is not well-defined.

Aim

The aim of this project is to delineate the spatiotemporal behaviour of numerous innate immune cell subsets during the different phases of CHS. In particular, we will be focusing on the behaviour of dermal dendritic cells (dDCs), perivascular macrophages (PVM) and mast cells.

Methods

Utilising the technique of intravital multiphoton microscopy, we have observed changes in the behaviour of the above-mentioned immune cell subsets following sensitisation with the hapten 2,4-dinitro-1-fluorobenzene (DNFB).

Results

Intravital imaging of homeostatic ear skin identified three migratory behaviours exhibited by dDCs as they interact with sessile PVM. Immediately post-sensitisation, a significant increase in the formation of stable cellular interactions were observed between dDCs and PVM. However, following mast cell degranulation, granule uptake by PVM resulted in the dissociation of these stable interactions. Hence, implying the potential egress of dDCs to the draining lymph nodes for T cell priming.

Conclusion

Our findings have identified a novel cellular mechanism involved in mediating the sensitisation phase of CHS. Further investigation into the molecular mechanisms regulating these cellular events will potentiate the identification of possible therapeutic targets.
T-bet deficiency impairs CD4 T cell effector trafficking to Influenza A Virus infected lungs but not their anti-viral functions
Authors: Dhume Kunal , Finn Caroline , McKinstry Karl Kai
Published: January 2023

CD4 T cell responses against Influenza A Virus (IAV) are predominantly classified as TH1, characterized by strong IFN-γ production. However, the protective role of IFN-γ is unclear, suggesting that full TH1 polarization may be dispensable for effective CD4 immunity. We test this hypothesis by analyzing transgenic CD4 T cells recognizing IAV that are deficient in the transcription factor T-bet (Tbx21−/−), the ‘master regulator’ of TH1 differentiation. 3×106 Wild-type (WT) or Tbx21−/− effector cells, primed under TH1 conditions, were transferred to naïve congenic WT mice then infected with lethal IAV. Tbx21−/− effectors protected mice, promoting similar reductions in viral titer and weight loss recovery as WT cells. However, T-bet deficiency impacted production of several cytokines by the effectors resulting in less IFN-γ and GM-CSF but more IL-2, IL-4 and IL-17. Although the peak magnitude of WT and Tbx21−/− effector responses were similar in secondary lymphoid organs, significantly fewer Tbx21−/− cells were observed in the lungs. We thus titrated effectors to 1×106 cells, to expose any potential differences in protection arising from differential lung homing. Lower effector transfer resulted in higher viral titer and delayed weight loss recovery in mice given Tbx21−/− versus WT cells. Mechanistically, Tbx21−/− cells expressed lower levels of the chemokine receptor CXCR3. CXCR3 blockade in mice given WT effectors reduced their numbers in the lungs and delayed weight loss recovery matching patterns seen in mice given Tbx21−/− effectors. Thus, while prototypical TH1 functions are dispensable for protection against IAV, T-bet-dependent chemokine responses are required to maximize anti-viral CD4 responses at the site of infection.