cytotoxic T cell

Examples of cytotoxic T cell in the following topics:

• Specific T-Cell Roles

  • T helper cells assist the maturation of B cells and memory B cells while activating cytotoxic T cells and macrophages.
  • Their primary functions include antigen presentation and activation of B cells, and activation of cytotoxic T cells and macrophages.
  • Cytotoxic T cells (TC cells, or CTLs) destroy virally infected cells and tumor cells, and are also cause much of the damage in in transplant rejection and autoimmune diseases.
  • Cytotoxic T cells recognize their antigen on pathogens through their T cell receptor, and will kill the pathogen through degranulation and cell-mediated apoptosis.
  • Effector memory cells may be either CD4+ or CD8+, and will produce either helper or cytotoxic T cells in a secondary immune response.

• Types of Adaptive Immunity

  • The adaptive immune response is mediated by B and T cells and creates immunity memory.
  • Cell mediated immunity is controlled by type 1 helper T-cells (Th1) and cytotoxic T-cells.
  • Helper-T cells facilitate the immune response by guiding cytotoxic T-cells to pathogens or pathogen-infected cells, while the cytotoxic T-cells will kill the pathogens or pathogen-infected cells.
  • Some of the ways in which cytotoxic T-cells kill pathogens include the release of granules that contain the cytotoxins perforin and granzyme, which lyse small pores in the membrane of a pathogen.
  • Helper-T cells will secrete cytokines, such as interferon-gamma, which can activate cytotoxic T-cells and macrophages.

• Classes of T Cells

  • T cells play a central role in cell-mediated immune response through the use of the surface T cell receptor to recognize peptide antigens.
  • Cellular immunity is mediated by T lymphocytes, also called T cells.
  • Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
  • Cytolytic or cytotoxic T cells (characterized by the expression of CD8 marker on their surface) kill cells that produce foreign antigens, such as cells infected by viruses and other intracellular microbes .
  • Distinguish between: naive, effector (helper and cytotoxic), memory and regulatory T cells

• Natural Killer Cells

  • Natural killer cells (NK cells) are cytotoxic lymphocyte critical to the innate immune system.
  • The role of NK cells is similar to that of cytotoxic T cells in the adaptive immune response.
  • Most of these receptors are not unique to NK cells and are present in certain T cells as well.
  • They serve to contain viral infections while the adaptive immune response is generating antigen-specific cytotoxic T cells that can clear the infection.
  • Schematic diagram indicating the complementary activities of cytotoxic T-cells and NK cells.

• Cell-Mediated Immunity

  • Cell-mediated immunity involves cytotoxic T cells recognizing infected cells and bringing about their destruction.
  • Unlike B cells, T lymphocytes (T cells) are unable to recognize pathogens without assistance.
  • Cytotoxic T cells mediate one arm of the cellular immune response
  • There are two main types of T cells: helper T lymphocytes (TH) and the cytotoxic T lymphocytes (TC).
  • The TH lymphocytes function indirectly to tell other immune cells about potential pathogens, while cytotoxic T cells (TC) are the key component of the cell-mediated part of the adaptive immune system which attacks and destroys infected cells.

• Natural Killer Cells

  • Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
  • Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
  • The role NK cells play is similar to that of cytotoxic T cells in the vertebrate adaptive immune response.
  • Schematic diagram indicating the complementary activities of cytotoxic T-cells and NK cells.
  • Schematic diagram indicating the complementary activities of cytotoxic T-cells and NK cells.

• Overview of Adaptive Immunity

  • The antigen is presented to immature helper T cells and cytotoxic T cells through binding the MHC II (helper T) or MHC I (cytotoxic T) to T-cell receptors.
  • Helper T cells activate B cells, which proliferate and produce antibodies specific to the antigen, while cytotoxic T cells destroy pathogens that bear the antigen that was presented to them by the APCs.
  • When B cells and T cells are activated, some will become memory cells.
  • Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.
  • Cytotoxic cells directly attack other cells carrying certain foreign or abnormal molecules on their surfaces.

• Antigen-Presenting Cells

  • Antigen presentation is a process where immune cells capture antigens and then enable their recognition by T-cells.
  • Some cells, however, are specially equipped to acquire and present antigen, and prime naive T cells.
  • Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.
  • MHC Class I molecules present antigen to CD8+ cytotoxic T cells.
  • Cytotoxic T cells (also known as TC, killer T cell, or cytotoxic T-lymphocyte (CTL)) are a population of T cells that are specialized for inducing the death of other cells.

• Maturation of T Cells

  • T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in the cell-mediated branch of the adaptive immune system.
  • T cells can be either helper T cells or cytoxic T cells based on whether they express CD4 (helper) or CD8 (cytotoxic) glycoprotein.
  • A thymocyte's differentiation into helper or cytotoxic versions is also determined during positive selection.
  • Double-positive cells (CD4+/CD8+) that are positively selected on MHC class II molecules will eventually become CD4+ helper T cells, while cells positively selected on MHC class I molecules mature into CD8+ cytotoxic T cells.
  • The remaining cells exit the thymus as mature naive T cells.

• Tests That Differentiate Between T Cells and B cells

  • Methods used to differentiate T cells and B cells include staining cell surface receptors and functional assays like the T lymphocyte cytotoxicity assay.
  • T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes.
  • T-lymphocytes can be distinguished from other lymphocytes like B cells and natural killer cells (NK cells) by the presence of a T cell receptor (TCR) on the cell surface.
  • Another functional assay used to identify T-lymphocyte is the cytotoxic activity assay.
  • Describe how T cells and B cells can be differentiated using staining of cell surface receptors and functional assays like the T lymphocyte cytotoxicity assay