Publications by authors named "Bellur S Prabhakar"

Progressive memory loss and cognitive dysfunction, encompassing deficits in learning, memory, problem solving, spatial reasoning, and verbal expression, are characteristics of Alzheimer's disease and related dementia. A wealth of studies has described multiple roles of the immune system in the development or exacerbation of dementia. Individuals with autoimmune disorders can also develop cognitive dysfunction, a phenomenon termed "autoimmune dementia.

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Background: Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to post-acute sequelae of SARS-CoV-2 (PASC) that can persist for weeks to years following initial viral infection. Clinical manifestations of PASC are heterogeneous and often involve multiple organs. While many hypotheses have been made on the mechanisms of PASC and its associated symptoms, the acute biological drivers of PASC are still unknown.

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Aberrant TGFβ signaling is linked to metastasis and tumor immune escape of many cancers including metastatic triple negative breast cancer (mTNBC). Previously, we have found that oncolytic adenoviruses expressing a TGFβ signaling inhibitory protein (sTGFβRIIFc) induced immune activation in a mouse TNBC (4T1) immunocompetent subcutaneous model with intratumoral injection. Systemic administration of adenoviruses can be a superior route to treat mTNBC but faces the challenges of increased toxicity and viral clearance.

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Background: The understanding of Post-acute sequelae of SARS-CoV-2 infection (PASC) can be improved by longitudinal assessment of symptoms encompassing the acute illness period. To gain insight into the various disease trajectories of PASC, we assessed symptom evolution and clinical factors associated with the development of PASC over 3 months, starting with the acute illness period.

Methods: We conducted a prospective cohort study to identify parameters associated with PASC.

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Recurrent waves of COVID19 remain a major global health concern. Repurposing either FDA-approved or clinically advanced drug candidates can save time and effort required for validating the safety profile and FDA approval. However, the selection of appropriate screening approaches is key to identifying novel candidate drugs with a higher probability of clinical success.

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Escalated innate immunity plays a critical role in SARS-CoV-2 pathology; however, the molecular mechanism is incompletely understood. Thus, we aim to characterize the molecular mechanism by which SARS-CoV-2 Spike protein advances human macrophage (Mϴ) inflammatory and glycolytic phenotypes and uncover novel therapeutic strategies. We found that human Mϴs exposed to Spike protein activate IRAK4 phosphorylation.

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Class-switched antinuclear autoantibodies produced by T follicular helper (TFH) cell-dependent germinal center (GC) B cell response play an essential pathogenic role in lupus nephritis (LN). The role of T follicular regulatory (TFR) cells, an effector subset of CD4Foxp3 T regulatory cells (Tregs), which are specialized in suppressing TFH-GC response and Ab production, remains elusive in LN. Contrasting reports have shown increased/reduced circulating TFR cells in human lupus that might not accurately reflect their presence in the GCs of relevant lymphoid organs.

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Increased tumor infiltrating lymphocytes (TIL) are associated with improved patient responses to immunotherapy. As a result, there is interest in enhancing lymphocyte trafficking particularly to colon cancers since the majority are checkpoint blockade-resistant and microsatellite stable. Here, we demonstrate that activated T-cells (ATC) armed with anti-CD3 x anti-EGFR bispecific antibody increases TIL and mediate anti-tumor cytotoxicity while decreasing tumor cell viability.

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Background: The generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response.

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Objective: Out-of-Hospital Cardiac Arrest (OHCA) is a global public health problem. There is inadequate data on OHCA in India. The Warangal Area out-of-hospital Cardiac Arrest Registry (WACAR) was planned to understand OHCA in a regional setting in India.

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TNF receptor superfamily comprises many T-cell costimulatory receptors, including TNFRSF1, TNFRSF2, TNFRSF4 (OX40), TNFRSF9 (4-1BB), TNFRSF18 (GITR), and TNFRSF7 (CD27). Signaling through these costimulatory stimulatory receptors can promote conventional T-cell (Tconv) proliferation, and effector functions in an antigen-dependent manner. Thus, agonistic antibodies and ligands for OX40, 4-1BB, GITR, and CD27 have been tested for inducing T-cell-mediated antitumor responses in several cancers.

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Type-1 Diabetes (T1D) is the major autoimmune disease affecting the juvenile population in which insulin-producing pancreatic β-cells are destroyed by self-reactive T-cells and B-cells. Emerging studies have identified the presence of autoantibodies and altered T-cell reactivity against several autoantigens in individuals who are at risk of developing T1D even before the clinical onset of diabetes. Whilst these findings could lead to the development of predictive biomarkers for early diagnosis, growing evidence on the generation of neoepitopes, epitope spreading and diverse antigen repertoire in T1D poses a major challenge for developing approaches to induce antigen-specific tolerance.

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LIGHT, also known as tumor-necrosis factor (TNF) superfamily member 14 (TNFSF14), is predominantly expressed on activated immune cells and some tumor cells. LIGHT is a pivotal regulator both for recruiting and activating immune cells in the tumor lesions. In this study, we armed human telomerase reverse transcriptase (TERT) promoter controlled oncolytic adenovirus with LIGHT to generate rAd.

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Foxp3T regulatory cells (Tregs) control autoimmune response by suppressing proliferation and effector functions of self-reactive Foxp3CD4/CD8 T cells and thereby maintain the critical balance between self-tolerance and autoimmunity. Earlier, we had shown that OX40L-JAG1 cosignaling mediated through their cognate receptors OX40 and Notch3 preferentially expressed on murine Tregs can selectively induce their proliferation in the absence of TCR stimulation. However, the differential molecular mechanisms regulating TCR-independent versus TCR-dependent Treg proliferation and lineage stability of the expanded Tregs remained unknown.

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Purpose: Anaplastic thyroid cancer (ATC) is rare but with poor prognosis. TRAIL can selectively induce apoptosis in cancer cells; however, resistance is quite common. Aim of our study was to evaluate TRAIL-induced apoptosis in ATC-derived cell lines, in vitro and in vivo, and the effect of combination with tyrosine kinase inhibitors (TKIs) selective for BRAF (vemurafenib) or Akt (MK-2206).

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In an effort to develop a new therapy for cancer and to improve antiprogrammed death inhibitor-1 (anti-PD-1) and anticytotoxic T lymphocyte-associated protein (anti-CTLA-4) responses, we have created a telomerase reverse transcriptase promoter-regulated oncolytic adenovirus rAd.sT containing a soluble transforming growth factor receptor II fused with human IgG Fc fragment (sTGFβRIIFc) gene. Infection of breast and renal tumor cells with rAd.

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ATC is an aggressive disease with limited therapeutic options due to drug resistance. TRAIL is an attractive anti-cancer therapy that can trigger apoptosis in a cancer cell-selective manner. However, TRAIL resistance is a major clinical obstacle for its use as a therapeutic drug.

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Anaplastic Thyroid Cancer (ATC) is an aggressive malignancy with limited therapeutic options and dismal patient survival. We have previously shown MADD to be differentially overexpressed in multiple cancer histologies and to contribute to tumor cell growth and survival. Therefore, we targeted MADD by gene silencing, explored its effect on cellular proliferation and metastases and examined its therapeutic potential in an orthotopic ATC model in athymic nude mice.

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Regulatory T-cells (Tregs) can facilitate immune evasion by tumor cells by dampening anti-tumor immunity. Reduced Teff/Treg ratio and enhanced Treg functional activity have been observed in patients suffering from different types of cancers, and attenuated Treg numbers/functions can serve as prognostic indicators. Normally, Tregs play an essential role in the maintenance of immune tolerance and prevention of autoimmunity.

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Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics.

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Background: Colorectal cancer remains a leading cause of cancer-related mortality worldwide. Metastases to the liver are often present at initial presentation and will form in most patients during their course of disease. We have previously demonstrated that enhanced trafficking and activation of tumor-infiltrating lymphocytes in colorectal liver metastases (CRLM) may improve antitumor immune responses.

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Self-tolerance, the state of unresponsiveness to self-tissues/antigens, is maintained through central and peripheral tolerance mechanisms, and a breach of these mechanisms leads to autoimmune diseases. Foxp3 + T-regulatory cells (Tregs) play an essential role in suppressing autoimmune response directed against self-antigens and thereby regulate self-tolerance. Natural Tregs are differentiated in the thymus on the basis of their higher TCR-affinity to self-antigens and migrate to the periphery where they maintain peripheral tolerance.

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Thyroid cancer incidence is increasing at an alarming rate, almost tripling every decade. In 2017, it was the fifth most common cancer in women. Although the majority of thyroid tumors are curable, about 2-3% of thyroid cancers are refractory to standard treatments.

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We have previously shown GM-CSF derived bone-marrow dendritic cells (G-BMDCs) can induce the selective expansion of Tregs through the surface-bound molecule OX40L; however, the physiological role of this ex vivo derived DC subset remained to be elucidated. We determined GM-CSF administration to mice induced the generation of in vivo derived OX40L DCs, phenotypically similar to ex vivo OX40LG-BMDCs, in the spleen, brachial lymph nodes and liver. The generation of OX40L DCs correlated with increased percentages of functionally suppressive Tregs in the spleen, brachial lymph nodes, and liver of GM-CSF treated mice.

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The immune system ensures optimum T-effector (Teff) immune responses against invading microbes and tumor antigens while preventing inappropriate autoimmune responses against self-antigens with the help of T-regulatory (Treg) cells. Thus, Treg and Teff cells help maintain immune homeostasis through mutual regulation. While Tregs can contribute to tumor immune evasion by suppressing anti-tumor Teff response, loss of Treg function can result in Teff responses against self-antigens leading to autoimmune disease.

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