Publications by authors named "Sampath Ramachandiran"

Article Synopsis
  • Current influenza vaccines work well for younger people but are less effective for the elderly due to age-related immune decline (immunosenescence).
  • Research on GPI-anchored cytokine-adjuvants combined with influenza hemagglutinin virus-like particles (HA-VLP) showed improved immune responses and reduced viral replication in aged mice compared to standard HA-VLP vaccines.
  • The study concludes that using cytokine-adjuvanted HA-VLP vaccines could potentially improve protection against influenza A virus for older adults, even without the presence of neutralizing antibodies.
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Several approaches have produced an effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since millions of people are exposed to influenza virus and SARS-CoV-2, it is of great interest to develop a two-in-one vaccine that will be able to protect against infection of both viruses. We have developed a hybrid vaccine for SARS-CoV-2 and influenza viruses using influenza virus-like particles (VLP) incorporated by protein transfer with glycosylphosphatidylinositol (GPI)-anchored SARS-CoV-2 RBD fused to GM-CSF as an adjuvant.

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Background: PD-L1 is one of the major immune checkpoints which limits the effectiveness of antitumor immunity. Blockade of PD-L1/PD-1 has been a major improvement in the treatment of certain cancers, however, the response rate to checkpoint blockade remains low suggesting a need for new therapies. Metformin has emerged as a potential new drug for the treatment of cancer due to its effects on PD-L1 expression, T cell responses, and the immunosuppressive environment within tumors.

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Dendritic cells (DCs) are the most effective antigen presenting cells for the development of T cell responses. The only FDA approved DC-based immunotherapy to date is Sipuleucel-T, which utilizes a fusion protein to stimulate DCs ex vivo with GM-CSF and simultaneously deliver the antigen PAP for prostate cancer. This approach is restricted by the breadth of immunity elicited to a single antigen, and to cancers that have a defined tumor associated antigen.

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Triple-negative breast cancer (TNBC) afflicts women at a younger age than other breast cancers and is associated with a worse clinical outcome. This poor clinical outcome is attributed to a lack of defined targets and patient-to-patient heterogeneity in target antigens and immune responses. To address such heterogeneity, we tested the efficacy of a personalized vaccination approach for the treatment of TNBC using the 4T1 murine TNBC model.

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Immune checkpoint inhibitor (ICI) immunotherapy improved the survival of head and neck squamous cell carcinoma (HNSCC) patients. However, more than 80% of the patients are still resistant to this therapy. To test whether the efficacy of ICI therapy can be improved by vaccine-induced immunity, we investigated the efficacy of a tumor membrane-based vaccine immunotherapy in murine models of HNSCC.

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The process of apoptosis is essential for maintaining the physiologic balance between cell death and cell growth. This complex process is executed by two major pathways that participate in activating an executioner mechanism leading to chromatin disintegration and nuclear fragmentation. Dysregulation of these pathways often contributes to cancer development and resistance to cancer therapy.

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Diffuse large B cell lymphoma (DLBCL) is the most common form of lymphoma in the United States. DLBCL comprises biologically distinct subtypes including germinal center-like (GCB) and activated-B-cell-like DLBCL (ABC). The most aggressive type, ABC-DLBCL, displays dysregulation of both canonical and noncanonical NF-κB pathway as well as genomic instability.

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Prior work using allogeneic bone marrow transplantation (allo-BMT) models showed that peritransplant administration of flagellin, a toll-like receptor 5 (TLR5) agonist protected murine allo-BMT recipients from CMV infection while limiting graft-vs-host disease (GvHD). However, the mechanism by which flagellin-TLR5 interaction promotes anti-CMV immunity was not defined. Here, we investigated the anti-CMV immunity of NK cells in C57BL/6 (B6) mice treated with a highly purified cGMP grade recombinant flagellin variant CBLB502 (rflagellin) followed by murine CMV (mCMV) infection.

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The inhibitors of apoptosis (IAP) are important regulators of apoptosis. However, little is known about the capacity of Smac mimetics (IAP inhibitor) to overcome virally associated-lymphoma's (VAL) resistance to apoptosis. Here, we explored the pro-apoptotic effect of a novel Smac mimetic, RMT5265.

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Paraquat, N-methyl-4-phenyl-1,2,3,6 tetrahydropyridine, and rotenone have been shown to reproduce several features of Parkinson's disease in animal and cell culture models. Although these chemicals are known to perturb dopamine homeostasis and induce dopaminergic cell death, their molecular mechanisms of action are not well defined. We have previously shown that paraquat does not require functional dopamine transporter and does not inhibit mitochondrial complex I in order to mediate its toxic action (Richardson et al.

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2,3,5-Tris-(glutathion-S-yl)hydroquinone (TGHQ), a reactive metabolite of the nephrotoxicant hydroquinone, induces the ROS-dependent activation of MAPKs, followed by histone H3 phosphorylation and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK(1)). Cell death and histone H3 phosphorylation are attenuated by pharmacological inhibition of p38 MAPK or ERK1/2 pathways. Because TGHQ, but not epidermal growth factor (EGF), induces histone H3 phosphorylation and cell death in LLC-PK(1) cells, we hypothesized that there are differences in the mechanisms by which TGHQ and EGF induce activation of the EGF receptor (EGFR).

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The tuberous sclerosis-2 (Tsc-2) gene is a suppressor of renal tumorigenesis and an early target of reactive oxygen species-induced renal cancer. Tuberin, the protein product of the Tsc-2 gene, participates in the regulation of cell proliferation, although the mechanism by which it suppresses proliferation is unknown. Quinol-thioether-transformed rat renal epithelial (QT-RRE) cell lines, derived from quinol-thioether-transformed primary renal epithelial cells from Eker rats, lack tuberin expression due to loss of heterozygosity of the Tsc-2 gene.

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Extracellular signal-regulated kinases (ERK1/2), c-Jun N-terminal kinases (JNK/SAPK), and p38 mitogen-activated protein kinase (MAPK) were all rapidly activated in a ROS-dependent manner during 2,3,5-tris-(glutathion-S-yl)hydroquinone (TGHQ)-mediated oxidative stress and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK1). TGHQ-induced phosphorylation of ERK1/2 and JNK MAPKs required epidermal growth factor receptor (EGFR) activation, whereas p38 MAPK activation was EGFR independent. In contrast to their established roles in cell survival, TGHQ-activated ERK1/2 and p38 MAPK (but not JNK) appear to contribute to cell death, since inhibition of ERK1/2 or p38 MAPKs with PD098059 or SB202190 respectively, attenuated TGHQ-mediated cell death.

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