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Concept of the Traditional Medicinal System and Holistic Health
Published in Mehwish Iqbal, Complementary and Alternative Medicinal Approaches for Enhancing Immunity, 2023
Helper T cells are classified into different types based on their cytokine levels. Helper T cells type 1 synthesise interleukin-2 and IFN-γ and are engaged in cellular immune and antiviral reactions, and the helper T cells type 2, which create interleukin-3, interleukin-4 and interleukin-5, are engaged in anti-parasitic and humoural reactions (Romagnani, 2000). Hence, T cells are responsible for putting together a suitable immune reaction in response to immunological challenge or stimulation, while the B cells, which are accountable for the synthesis of immunoglobulin or antibodies, are the other lymphocytes of the adaptive immune system.
Acquired Immunity
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
T- and B-cell immunity extends the ability to fight infection and cancers. In contrast to phagocytes which only recognize extracellular organisms (mostly bacteria), T cells can combat intracellular infections such as viruses as well as organisms that parasitize macrophages such as fungi, and some bacteria (e.g. mycobacteria, legionella, listeria, brucella and salmonella). Such intracellular infections are controlled by cytotoxic and helper T lymphocytes. Cytotoxic T cells recognize tiny fragments of virus or cancer antigen that are expressed on the surface of affected cells and destroy the cell and pathogen within it. Helper T cells produce cytokines that activate macrophages to kill organisms within them and further activate cytotoxic cells because they are unable to destroy cells or pathogens directly. Helper T cells also activate NK cells to kill virally infected and tumour cells. Antibody has potent neutralizing actions on viruses and toxins and participates in antigen presentation. It also enhances innate immunity by opsonizing foreign particles.
Short-Term Exercise and Immune Function
Published in Ronald R. Watson, Marianne Eisinger, Exercise and Disease, 2020
Clearly, the immunological information for the cell-mediated immune response is carried by the different populations of T–lymphocytes. There are three general categories of lymphocytes: T-cells, B-cells, and null cells. The lymphocytes whose specific functions are coded in the thymus are called T-lymphocytes; they include helper T-cells, cytotoxic T-cells, and suppressor T-cells. These three populations of sensitized T-lymphocytes are responsible for providing cell–mediated immunity through their specific functions. Helper T-cells recognize an abnormal body cell or an intruder. If such a cell is detected, they send out a chemical messenger to the cytotoxic T-cells (also called killer T-cells), and the latter actively attack the abnormal cell. Helper T-cells also play a regulatory role in humoral immunity by activating B-cells and plasmocytes to release antibodies. On the other hand, suppressor T-cells are the necessary feedback mechanism to control the destructive process initiated by the helper T-cells.
Pulmonary delivery of resveratrol-β-cyclodextrin inclusion complexes for the prevention of zinc chloride smoke-induced acute lung injury
Published in Drug Delivery, 2022
Wanmei Wang, Yan Liu, Pan Pan, Yueqi Huang, Ting Chen, Tianyu Yuan, Yulong Ma, Guang Han, Jiahuan Li, Yiguang Jin, Fei Xie
T cells play an important role in the immune system, especially the helper T cell subsets. CD4+ T cells can be categorized into four subtypes according to their own functions. Th0 cells can differentiate to Th1, Th2, Treg, and Th17 cells under different conditions. The imbalances of Th1/Th2 and Treg/Th17 are the important mechanisms in the pathogenesis of many diseases, such as ALI (Zhang et al., 2016), allergic rhinitis (Yu et al., 2017), and cancer (Lin et al., 2019). T lymphocytes subsets, especially CD4+ T helper cells contribute to the advancement of autoimmune and inflammatory diseases (Zhang et al., 2016). The molecular aspects involved in the pathogenesis of ZnCl2 smoke-induced ALI are poorly defined. This study suggested that the imbalance of Th1/Th2 and Treg/Th17 may be involved in the pathogenesis of ZnCl2 smoke-induced ALI. Our result is consistent with a recent study demonstrating that rats with smoke exposure showed significant imbalance in Treg/Th17 (Zhang et al., 2016). Moreover, a recent study revealed a previously unexpected role of immune responses that increase alveolar permeability in ARDS (Li et al., 2015). RES-β-CD has an advantage in regulating immune response compared with BUD for the ALI induced by ZnCl2 smoke. Besides, it must be noticed that inhaled BUD could cause immunosuppression in the localized airways (Tashkin et al., 2019).
An update on COVID-19 pandemic: the epidemiology, pathogenesis, prevention and treatment strategies
Published in Expert Review of Anti-infective Therapy, 2021
Hin Fung Tsang, Lawrence Wing Chi Chan, William Chi Shing Cho, Allen Chi Shing Yu, Aldrin Kay Yuen Yim, Amanda Kit Ching Chan, Lawrence Po Wah Ng, Yin Kwan Evelyn Wong, Xiao Meng Pei, Marco Jing Woei Li, Sze-Chuen Cesar Wong
The synthesis of type I interferons (IFN) is activated after viral invasion, promoting downstream JAK-STAT signal pathway for increased expression of IFN-stimulated genes (ISGs). Spreading of the virus is restricted by antigen-presenting macrophage and NK cells [39,40]. Blocking of IFN production by the N protein of SARS-CoV is important for viral survival directly [39,40]. The prolonged incubation period of viral infection effectively helps the virus escape from the innate immune response at early stage of infection theoretically [35]. Innate immune responses of type I IFN and monocyte-macrophages need to be further investigated in COVID-19 patients, as the dysregulated innate immune response caused lethal pneumonia in young SARS-CoV-2-infected patients [35]. In adaptive immunity, Th1 type immune response is important to virus clearance. Helper T cells activate T-dependent B cells for viral-specific antibodies promotion. Cytotoxic T cells kill virus-infected cells directly. Particularly, helper T cells promotes NF-kB signaling pathway for proinflammatory cytokines introduction [40]. Limited serology study showed the neutralization effect in Vero E6 cells with 5 COVID-19 patient sera that were IgG-positive. All patient sera were able to neutralize 100 TCID50 (50% tissue-culture-infective dose) of COVID-19 in titer 1:40 through 1:80 [33].
Diagnosis of SARS-CoV-2 infection in the setting of the cytokine release syndrome
Published in Expert Review of Molecular Diagnostics, 2020
Marwan M. Azar, Junghee J. Shin, Insoo Kang, Marie Landry
Laboratory testing is central to both the initial diagnosis and follow-up of SARS-CoV-2 infection and can moreover provide early clues of progression to CRS. Laboratory findings associated with COVID-19 include decreased lymphocyte counts, platelet counts and albumin levels as well as elevated CRP, ferritin, lactate dehydrogenase (LDH), transaminases, D-dimer, procalcitonin and interleukin-6 and 10 levels among others. In retrospective case series of 393 patients with COVID-19 in New York, lymphopenia was present in 90% of cases, elevated ferritin in 66%, elevated CRP in 43%, elevated D-dimer in 36%, elevated alanine aminotransferase in 32% and elevated procalcitonin in 17% [88]. In addition to aiding in the initial diagnosis of COVID-19, several biomarkers may serve as indicators of greater disease severity at baseline as well as markers of disease progression, often a clinical manifestation of developing CRS. CRP is perhaps the best predictor of COVID-19 severity. Elevated CRP levels have been associated with more severe disease at baseline, more extensive lung infiltrates on imaging and increasing CRP levels are a risk factor for COVID-19 progression [89,90]. Decreased lymphocytes counts and increased LDH levels have also been associated with severe COVID-19 both as individual biomarkers and when integrated into severity prediction indexes [91,92]. Immune dysregulation is also manifested by higher neutrophil-lymphocyte-ratio, and lower percentages of monocytes, eosinophils, and basophils. Moreover, decreased T-cells subsets, particularly helper T cells have been observed with severe disease [31].