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Infection and Inflammation
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Erik H. J. G. Aarntzen, Andor W. J. M. Glaudemans
Lymphocytes: Multiple in vitro studies have shown increased glucose metabolism in different stages of functional differentiation of T cells [61]. When a naïve T cell encounters its cognate antigen in the proper stimulatory context, it undergoes a transcriptional program that is characterized by proliferation, rapid growth, and induction of specialized effector functions belonging to effector T cells. This reprogramming requires metabolic adaption from a catabolic metabolism to an anabolic metabolism because, unlike quiescent states, nutrients will not be used for homeostasis but will be incorporated in biosynthetic precursors required for daughter cells and effector functions. This demand for biosynthetic precursors drives effector T cells to increase their glycolysis, even in the presence of sufficient levels of oxygen. To the contrary, T cells destined to become memory cells must maintain catabolic metabolism, underlying their longevity and may postpone their terminal differentiation, so they rely mainly on mitochondrial fatty acid oxidation.
Molecular Analysis of Immunity
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Antigen-inexperienced naïve T cells circulate through the lymphoid tissues and organs until antigen is presented to them by professional APCs such as B cells, macrophages and dendritic cells.40,51 The recognition of antigen in association with costimulatory molecules, such as B7 expressed on the APC surface,52-55 results in the activation of naïve T cells, their rapid proliferation, and elaboration of effector’ T cell function and phenotype.56,57 After the antigenic load has been controlled by the immune response, effector T cells die off and a low frequency of antigen-specific resting ‘memory’ T cells remains. These cells are able to be subsequently stimulated by any cell expressing their cognate antigen in association with the appropriate class of MHC molecule.56 Although the majority of CD8+ T cells perform cytotoxic functions, CD4 helper T cells may divide into Th1 and Th2 types.58 These can be differentiated by expression of different surface makers and their function. Whereas Th1 cells produce cytokines and other factors which aid in the activation of macrophages and CTL,58-60 Th2 cells produce cytokines involved in the activation of B cells and the generation of humoral immunity,61-64 T cell phenotype is typically measured by flow cytometry using antibodies specific for the various cells surface markers.65 A summary of the phenotypic and functional attributes of naïve, effector and memory T cells is given in Table 1. The terms ‘bright’ and ‘dim’ refer to their appearance by flow cytometry. As one can see, this table differs from the rigid definitions given in most textbooks; this is to emphasize that expression of these phenotypic and functional markers is rarely all-or-none, but rather fluid and interchangeable.
Applications of Antiviral Nanoparticles in Cancer Therapy
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Anusha Konatala, Sai Brahma Penugonda, Fain Parackel, Sudhakar Pola
To overcome tumour tolerance, vaccination can be used to enhance antitumour responses. Immunotherapy could be a potential approach in targeting the specific antigens of the tumours and can be sensitised to the host immune system (Jonuleit et al. 2016). Dendritic cells are well known for triggering naive T-cells and the adaptive immune responses (Schuler et al. 2003). This generally results in the reduction of cancer progression.
A mathematical model of cytotoxic and helper T cell interactions in a tumour microenvironment
Published in Letters in Biomathematics, 2018
Heidi Dritschel, Sarah L. Waters, Andreas Roller, Helen M. Byrne
T cells are one of the most important components of the immune system in the fight against cancer. They originate from pluripotent haematopoietic stem cells in the bone marrow which migrate to the thymus where they mature into naive T cells. The naive T cells move to the lymph nodes where they become activated on contact with their cognate antigens. Activated T cells proliferate rapidly to produce a substantial army of antigen-specific T cells. These short lived T cells are then transported through the blood vessels to the tumour where they bind to and kill infected cells and also produce cytokines that recruit other immune cells to the tumour. This process continues until either the tumour has been removed or the tumour adapts to, and evades, targetting by the T cells (Chen and Mellman, 2013; Janeway et al., 2001).
Genetic variants affecting chemical mediated skin immunotoxicity
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Isisdoris Rodrigues de Souza, Patrícia Savio de Araujo-Souza, Daniela Morais Leme
Langerhans cells (LC) are professional APCs of the epidermis that migrate to lymph nodes and stimulate T lymphocyte responses (Clayton et al. 2017; Quaresma 2019). As a dendritic cell (DC), LC might capture, process, and present antigens to naïve T cells (Klechevsky 2015). During skin sensitization, LC mobilization towards the regional lymph nodes and concomitant maturation (to DCs) are induced and regulated by cutaneous cytokines. Thus, LC process and present the captured antigen on their surface associated with MHC molecules. This complex may be subsequently recognized by naïve T cells, thus instigating clonal expansion of antigen‐specific T lymphocytes and enabling development of cellular immunological memory (Divkovic et al. 2005).