26 research outputs found

    Facilitation of Wound Healing Following Laparoscopic and Conventional Abdominal Surgery with Dressings, Patches, Antibiotics, etc.

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    Wounds due to surgical incisions and due to injuries often do not heal and can result in complications like slow healing and infections. Several approaches to facilitate wound healing are constantly being developed. Here we discuss various wounds and multiple ways to treat wounds especially those resulting from abdominal surgery either due to conventional surgery or due to laparoscopic surgery. In future, there are various possibilities in the pipeline that could result in accelerated wound healing as well as tissue regeneration

    Viral infection: an evolving insight into the signal transduction pathways responsible for the innate immune response

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    The innate immune response is initiated by the interaction of stereotypical pathogen components with genetically conserved receptors for extracytosolic pathogen-associated molecular patterns (PAMPs) or intracytosolic nucleic acids. In multicellular organisms, this interaction typically clusters signal transduction molecules and leads to their activations, thereby initiating signals that activate innate immune effector mechanisms to protect the host. In some cases programmed cell death-a fundamental form of innate immunity-is initiated in response to genotoxic or biochemical stress that is associated with viral infection. In this paper we will summarize innate immune mechanisms that are relevant to viral pathogenesis and outline the continuing evolution of viral mechanisms that suppress the innate immunity in mammalian hosts. These mechanisms of viral innate immune evasion provide significant insight into the pathways of the antiviral innate immune response of many organisms. Examples of relevant mammalian innate immune defenses host defenses include signaling to interferon and cytokine response pathways as well as signaling to the inflammasome. Understanding which viral innate immune evasion mechanisms are linked to pathogenesis may translate into therapies and vaccines that are truly effective in eliminating the morbidity and mortality associated with viral infections in individuals

    Robust Intrapulmonary CD8 T Cell Responses and Protection with an Attenuated N1L Deleted Vaccinia Virus

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    BACKGROUND: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the immunogenicity of an attenuated strain of vaccinia virus engineered to inactivate the N1L gene (vGK5). Using the intranasal route, this recombinant virus was 2 logs less virulent compared to the wildtype VACV-WR. Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs. VACV-specific antibodies were also detected in the sera of mice infected 3-5 months prior with the attenuated vGK5 virus. Finally, mice immunized with vGK5 were significantly protected when challenged with a lethal dose of VACV-WR. CONCLUSIONS: These results indicate that the attenuated vGK5 virus protects against subsequent infection and suggest that the N1L protein limits the strength of the early antiviral CD8 T cell response following respiratory infection

    Exploring the potential benefits of vaccinia virus complement controlprotein in controlling complement activation in pathogenesis of the central nervous system diseases

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    Aging is a major risk factor for the development of diseases related to the central nervous system (CNS), such as Alzheimer's disease (AD) and age-related macular degeneration (AMD). In both cases, linkage studies and genome-wide association studies found strong links with complement regulatory genes and disease risk. In AD, both CLU and CR1 genes were implicated in the late-onset form of the disease. In AMD, polymorphisms in CFH, CFB and C2 were similarly implicated. The cost of caring for patients with AD or AMD is approaching billions of dollars, and with the baby boomers reaching their 60's, this amount is likely to increase further. Intervention using complement inhibitors for individuals in their early 50s who are at a higher risk of disease development, (testing positive for genetic risk factors), could slow the progression of AD or AMD and possibly prevent the severity of late stage symptoms. Although we have used the vaccinia virus complement control protein (VCP) to elucidate the role of complement in CNS diseases, it has merely been an investigational tool but not the only possible potential therapeutic agent

    Modulation of Gamma Interferon-Induced Major Histocompatibility Complex Class II Gene Expression by Porphyromonas gingivalis Membrane Vesicles

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    Gamma interferon (IFN-γ)-induced endothelial cells actively participate in initiating immune responses by interacting with CD4(+) T cells via class II major histocompatibility complex (MHC) surface glycoproteins. Previously, Porphyromonas gingivalis membrane vesicles were shown to selectively inhibit IFN-γ-induced surface expression of HLA-DR molecules by human umbilical cord vascular endothelial cells. In this study, we demonstrated an absence of HLA-DRα mRNA from IFN-γ-induced cells in the presence of P. gingivalis membrane vesicles by using reverse transcriptase-PCR and Southern blotting. Vesicles also prevented transcription of the gene encoding class II transactivator, a transactivator protein required for IFN-γ-induced expression of MHC class II genes. In addition, the effects of vesicles on IFN-γ signal transduction involving Jak and Stat proteins were characterized by using immunoprecipitation and Western blot analyses. Jak1 and Jak2 proteins could not be detected in endothelial cells treated with membrane vesicles. Consequently, IFN-γ-induced phosphorylation of Jak1, Jak2, and Stat1α proteins was prevented. The class II-inhibitory effect of the membrane vesicles could be eliminated by heating vesicles at 100°C for 30 min or by treating them with a cysteine proteinase inhibitor. This indicates that the cysteine proteinases were most likely responsible for the absence of Jak proteins observed in vesicle-treated cells. The observed increased binding of radiolabeled IFN-γ to vesicle-treated cells suggests that vesicles may also modulate the IFN-γ interactions with the cell surface. However, no evidence was obtained demonstrating that vesicles affected the expression of IFN-γ receptors. Thus, P. gingivalis membrane vesicles apparently inhibited IFN-γ-induced MHC class II by disrupting the IFN-γ signaling transduction pathway. Vesicle-inhibited class II expression also occurred in other IFN-γ-inducible cells. This suggested that the ability of P. gingivalis membrane vesicles to modulate antigen presentation by key cells may be an important mechanism used by this particular bacterium to escape immunosurveillance, thereby favoring its colonization and invasion of host tissues

    Structure of vaccinia complement protein in complex with heparin and potential implications for complement regulation

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    Vaccinia virus complement control protein (VCP), a homolog of the regulators of the complement activation family of proteins, inhibits complement activation through mechanisms similar to human fluid-phase complement regulators factor H and C4b-binding protein. VCP has a heparin-binding activity that assists vaccinia in host interactions. Interaction with cell-surface polyanions like heparin is centrally important in the functioning of fluid-phase complement regulators and is the basis of host-target discrimination by the alternative pathway. We report the structure of VCP in complex with a heparin decasaccharide, which reveals changes in VCP that might be pertinent to complement regulation. Properties that VCP shares with fluid-phase complement regulators suggest that such conformational changes may be of relevance in the functioning of other complement regulators. Additionally, comparison of VCP–heparin interactions with potentially similar interactions in factor H might enable understanding of the structural basis of familial hemolytic uremic syndrome, attributed to mutational disruption of heparin and C3b binding by factor H

    Characterization of poxvirus-encoded proteins that regulate innate immune signaling pathways

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    Innate immune recognition of pathogens is critical to the prompt control of infections, permitting the host to survive to develop long-term immunity via an adaptive immune response. Poxviruses encode a family of proteins that inhibit signaling by Toll-like receptors to their downstream signaling components, severely limiting nuclear translocation of transcription factors such as IRF3 and NF-kappaB and thereby decreasing production of host interferons and cytokines. We describe bioinformatics techniques for identifying candidate poxviral inhibitors of the innate immune response based on similarity to the family of proteins that includes A52, A46, and N1. Robust luciferase assays can determine whether a given poxviral gene affects innate immune signaling, and in combination with other approaches can identify the cellular targets of poxviral innate immune evasion genes. Because apoptosis is an innate immune response of the cell to viral infection, assays for identifying poxviral genes that inhibit apoptosis can also be employed. Novel poxviral innate immune inhibitors are being identified via several approaches and these techniques promise to identify further complexities in the way that poxviruses interact with the host innate immune system
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