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The Inducible System: History of Development of Immunology as a Component of Host-Parasite Interactions
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Antigen recognition is restricted by self-recognition both for the initiation of an immune response by helper T lymphocytes and for the killing of virally infected cells by cytotoxic lymphocytes. The major histocompatibility complex gene products that restrict antigen recognition by helper lymphocytes (the so-called class II MHC proteins) are different from the products that restrict antigen recognition by cytotoxic lymphocytes (class 1 MHC proteins). Class I MHC proteins are found on the surfaces of all vertebrate cells. Their role is to present antigens arising in the cytoplasm of target cells to cytotoxic T lymphocytes. Typically these are viral antigens displayed by virally infected cells. Class II MHC antigens, however, are only found on the surfaces of antigen presenting cells. Their function is to present antigen taken up by APC through phagocytosis to the helper T cell. The helper T cell then helps trigger a humoral immune response. The selective advantage of two functionally distinct sets of MHC proteins may be to prevent cytotoxic lymphocytes from destroying APCs that are presenting antigen for the initiation of the immune response.
Dermal filler complications and management
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
Cytotoxic T lymphocytes can be perceived as the assassins of the immunological world. Once activated, they will target and destroy cells infected with a specific pathogen. The previously discussed NK cells can target a wide range of infected cells, whereas cytotoxic T lymphocytes will only attack cells infected with pathogens they recognise. Their method of destroying infected cells is relatively similar to NK cells, with the insertion of perforin proteins, as well as pumping toxic chemicals such as granulysin and lymphotoxin to induce apoptosis within the target cell. To ensure that rogue antigens and escaping microbes are not allowed to wreak havoc elsewhere, cytotoxic T lymphocytes secrete IFN-γ, which attracts and activates phagocytes as well as macrophage migration factor to keep them at the site of infection where they are required most.
Order Blubervirales: Surface Protein
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The ability of the added CpG as an adjuvant to enhance immunogenicity of Engerix-B vaccine has been approved before in a phase I/II clinical study for the first clinical evaluation of the safety, tolerability, and immunogenicity of CpG when added to this commercial HBV vaccine (Cooper et al. 2004, 2005; Siegrist et al. 2004; Payette et al. 2006). Strikingly, when the patients were immunized with the Engerix-B vaccine together with CpGs, the protective levels of anti-HBs IgG were developed within just two weeks after application of the priming vaccine dose. A trend toward higher rates of specific cytotoxic T lymphocyte (CTL) responses has been also reported.
COVID-19 during Pregnancy and Postpartum:
Published in Journal of Dietary Supplements, 2022
Sreus A. G. Naidu, Roger A. Clemens, Peter Pressman, Mehreen Zaigham, Kamran Kadkhoda, Kelvin J. A. Davies, A. Satyanarayan Naidu
The immunological imprint established by the original virus infection governs the antibody response thereafter, which is conventionally known as the doctrine of the “Original Antigenic Sin”. Some viruses (e.g. CoVs, HIV, HBV) are initially controlled by cytotoxic T-lymphocytes, but may subsequently escape through mutation of the relevant T-cell epitope. Some of these mutations preserve the normal binding to MHC class-I molecules, but present an altered surface to the T-cell antigen receptor (Klenerman and Zinkernagel 1998). Therefore, human individuals primed with a virus (i.e. SARS-CoV) may respond to a subsequent infection by related virus bearing-epitope variant (i.e. SARS-CoV-2) with a CTL response directed against the initial epitope rather than against the new variant epitope. This phenomenon of 'original antigenic sin (OAS)' was initially described with influenza and is an asymmetric pattern of protective antibody cross-reactivity determined by exposure to previously existing strains. OAS leads to impaired clearance of variant viruses infecting the same individual and may enhance the immune escape of mutant viruses evolving in an individual host.
In vitro determination of the immunosuppressive effect, internalization, and release mechanism of squalene-gusperimus nanoparticles for managing inflammatory responses
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Carlos E. Navarro Chica, Tian Qin, Bart J. de Haan, M.M Faas, Alexandra M. Smink, Ligia Sierra, Betty L. López, Paul de Vos
This study aimed to characterize the in-vitro action of Sq-GusNPs as an anti-inflammatory agent as well as to elucidate how these NPs are internalized and maintain the therapeutic effect of gusperimus. As gusperimus has shown to exert its immunosuppressive effects in both innate and adaptative arms of the immune system [3] we studied the anti-inflammatory and anti-proliferative effects of Sq-GusNPs on macrophages and T-cells. Macrophages are key players of the innate immune system. They have three major functions, i.e. serving as antigen-presenting cells, to phagocytose, and to immunomodulate the microenvironment through secretion of various cytokines and growth factors [17]. T lymphocytes are in general the key players of the adaptative cellular immune responses and cytotoxic T lymphocytes are responsible for its effector function. Cytotoxicity towards T lymphocytes is exerted directly through the Fas or perforin pathway and/or indirectly by the release of cytokines [18].
Immunoscore: a novel prognostic tool. Association with clinical outcome, response to treatment and survival in several malignancies
Published in Critical Reviews in Clinical Laboratory Sciences, 2020
Silverio Ros-Martínez, Diana Navas-Carrillo, José Luis Alonso-Romero, Esteban Orenes-Piñero
TILs are a heterogeneous population comprising mainly T-lymphocytes, and to a lesser degree, B lymphocytes and natural killer cells. It is important to analyze TILs subsets separately due to their different physiological and pathological effects in the tumor microenvironment. Contrary to infiltration of cells (macrophages, B-lymphocytes, eosinophils or mast cells) responsible for chronic inflammation, the presence of high numbers of T-lymphocytes has been reported to be an indicator of good prognosis in cancers such as colon cancer (CC) [7], melanoma [8], lung carcinoma [9], pancreatic cancer [10], hepatocellular carcinoma (HCC) [11], breast cancer [12] and even brain metastases (BMs) [13], among others. With the development of immunohistochemistry, more subtypes of TILs have been discovered. CD3+, a biomarker of T-lymphocytes, is expressed in almost all T-lymphocytes. In addition, T-lymphocyte cell surface markers include mainly the following subtypes: CD8+ cytotoxic T-lymphocytes (CTL), CD4+ T helper lymphocytes (Th), CD45RO+ memory T cells and FOXP3+ regulatory cells (Tregs), among others [14].