A Review of Classic Physiological Systems
Len Wisneski in The Scientific Basis of Integrative Health, 2017
T lymphocytes differentiate into five distinct varieties:Cytotoxic T cells, which are capable of destroying virus-infected or foreign cells.Killer T cells, which recognize and obliterate specific antigens. They look for their target antigen and, like smart bombs, they blast a hole in the cell membrane. The cell essentially explodes and the contents are lost.Helper T cells, which prepare the antigen so that it is easier for the B cells to destroy them. They also assist in T-cell maturation.Suppressor T cells, which suppress the immune response of both T and B cells when the antigen is destroyed. They act by suppressing the helper cells or by inhibiting activated lymphocytes.Memory T cells, which have the capacity to remember previous exposure to an antigen and, thus, to hasten the immune response. They reside in the lymphatic system until called into action. This is called the secondary immune response.
Chemokines and Chemokine Receptor Interactions and Functions
Thomas R. O’Brien in Chemokine Receptors and AIDS, 2019
After exposure to antigen, immunological memory is induced (i.e., the next time antigen is encountered there is a rapid response), suggesting the existence of memory T cells that are partially activated and able to orchestrate rapid secondary responses. These cells can be distinguished from naïve T cells by their expression of several cell surface molecules, including the CD45RO isoform, and by their enhanced ability to respond to antigen. Recent studies suggest that CD45RO+ cells can be divided into true memory cells and effector memory cells by their expression of certain chemokine receptors. CCR7 expressing true memory cells bear lymph node homing receptors, including L-selectin. True memory cells lack immediate effector function, but can efficiently stimulate dendritic cells and differentiate into CCR7 negative effector cells upon secondary stimulation. CCR7 negative memory cells express receptors for migration into inflamed tissues and display immediate effector function (49).
Role of Epigenetics in Immunity and Immune Response to Vaccination
Mesut Karahan in Synthetic Peptide Vaccine Models, 2021
The second type of adaptive immunity is cell-mediated immunity. Cell-mediated immunity functions via T cells which are released into circulation following their maturation in the thymus. T cells are categorized as CD4+ cells and CD8+ cells according to the type of T cell receptor (TCR) they express. The helper T cells express CD4 receptors while cytotoxic T cells express CD8 TCR (Margolick, Markham, and Scott 2006). There are two types of helper T cells, Th1 and Th2. Th1 cells are involved in cell-mediated immunity and Th2 cells are involved in antibody-mediated immunity (O’Garra and Arai 2000). In contrast to B cells, T cells require antigen processing by antigen-presenting cells for antigen recognition. Following activation and clonal expansion, memory T cells are produced to induce a rapid immune response for subsequent infections (Pennock et al. 2013). Following their formation, memory T cells can provide immunity for approximately ten years (Hammarlund et al. 2003).
Phenylboronic ester-modified polymeric nanoparticles for promoting TRP2 peptide antigen delivery in cancer immunotherapy
Published in Drug Delivery, 2022
Qiyan Wang, Zhipeng Dong, Fangning Lou, Yunxue Yin, Jiahao Zhang, Hanning Wen, Tao Lu, Yue Wang
As we all known, memory T-Cell play a vital role in developing a long-term protection to fight against the second attack of pathogen infection. So, we tested the induction of memory T cells in restimulated splenocyte from vaccinated mice. Memory T cells are classified to central memory T cell (TCM) and effector memory T cells (TEM). TCM, highly expressing molecule CD62L, showed higher antitumor activities than TEM. After restimulating, these cells were stained by CD44-APC, CD62L-PE to analyze percentage of TCM. As shown in, PEG-b-PAsp-g-PBE/TRP2 group showed significant increase (10%) in the CD8+ TCM population (CD8+CD44+ CD62L+), compared with untreated mice. In contrast, treatment with TRP and PEG-b-PAsp/TRP2 induced the generation of slightly more (2.4%, 3.9%) TCM than vaccination with PBS group. Similarly, in CD4+ TCM analysis, PEG-b-PAsp-g-PBE/TRP2 group elicited significantly higher central memory T cells than other groups (Figure 9). Taken together, typical flow cytometry results of PEG-b-PAsp-g-PBE/TRP2 adjuvant-free nanovaccine can induce the strong memory T-cell immune response for long-term prevention against tumors.
Innate and adaptive immune responses in respiratory virus infection: implications for the clinic
Published in Expert Review of Respiratory Medicine, 2020
John Stambas, Chunni Lu, Ralph A Tripp
Memory T cells have an important function in protection following re-exposure to viral pathogens. After initial virus clearance, T cells undergo apoptosis and only a small proportion survive as long-lived recirculating antigen-specific memory cells (reviewed in [87]). These long-lived antigen-specific memory T cells can initiate strong recall responses with accelerated kinetics when compared to the primary immune response. The recent description and characterization of tissue-resident memory cells (Trm), i.e. memory cells that do not recirculate, highlights the importance of this distinct population for rapid responses when pathogens are re-encountered. For example, analysis of human lung tissue following influenza virus infection indicated the presence of CD8+Trm that could proliferate and were highly polyfunctional [88]. Trials in RSV-infected adults have shown that tissue-resident RSV-specific CD8 T cells in bronchial samples are found at higher frequencies when compared to those in peripheral blood and that the higher frequency of cells correlated with lower viral loads and disease symptoms [89].
Percutaneous BCG enhances innate effector antitumor cytotoxicity during treatment of bladder cancer: a translational clinical trial
Published in OncoImmunology, 2019
Niannian Ji, Neelam Mukherjee, Edwin E. Morales, Maggie E. Tomasini, Vincent Hurez, Tyler J. Curiel, Getahun Abate, Dan F. Hoft, Xiang-Ru Zhao, Jon Gelfond, Sourindra Maiti, Laurence J.N. Cooper, Robert S. Svatek
Durable immunity requires memory T cells with long-term homeostatic proliferation capacity that can both expand and produce effector functions in response to antigenic challenges.18–20 To assess the relative numbers of BCG-specific T cells with the capacity for both expansion and cytokine production, we used CFSE dilution to track lymphoproliferation coupled with intracellular staining to detect IFN-γ production (Supplemental Figure S4A) as described.21 As expected, we observed higher numbers of proliferating IFN-γ producing T cells in PPD converted compared to PPD unconverted prime patients (Supplemental Figure S4B-D). At 3 months after priming, the number of proliferating IFN-γ producing T cells, including γδ T cells, was significantly increased (Figure 3C). This effect of priming on γδ T cells suggests induction of a memory-like γδ T cell similar to the phenotype we reported in BCG vaccinated populations.22 At 6 months from baseline, however, the number of these cells was no longer increased, indicating that the effects of priming on long-term homeostatic proliferating memory T cells may wane over time. Taken together, the results indicate that priming enhances long-term BCG-specific memory T cell responses, but responses are transient and appear to plateau at 3 months following priming.
