T lymphocytes

(noun)

These cells, also called T cells, belong to a group of white blood cells known as lymphocytes and play a central role in cell-mediated immunity. 

Related Terms

  • Central tolerance
  • thymus
  • thymocyte

Examples of T lymphocytes in the following topics:

  • 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.
    • T-lymphocytes express CD3, CD4, CD8, or CD25 markers.
    • Another functional assay used to identify T-lymphocyte is the cytotoxic activity assay.
  • Clonal Selection and Tolerance

    • Regulatory T cells can be considered both central tolerance and peripheral tolerance mechanisms, as they can be generated from self (or foreign)-reactive T cells in the thymus during T cell differentiation.
    • clonal selection of the B and T lymphocytes:1.
    • Immature lymphocytes with various receptors 3.
    • Mature, inactive lymphocytes 5.
    • Cloned activated lymphocytes.
  • Cytotoxic T Lymphocytes and Mucosal Surfaces

    • On maturation, T and B lymphocytes circulate to various destinations.
    • Lymph nodes scattered throughout the body house large populations of T and B cells, dendritic cells, and macrophages .
    • The spleen houses B and T cells, macrophages, dendritic cells, and NK cells .
    • The spleen is also the site where APCs that have trapped foreign particles in the blood can communicate with lymphocytes.
    • Lymph nodes are filled with lymphocytes that purge infecting cells.
  • Development of the Dual Lymphocyte System

    • B cells and T cells are the major types of lymphocytes.
    • B cells mature into B lymphocytes in the bone marrow, while T cells migrate to, and mature in, a distinct organ called the thymus.
    • The lymphocytes involved in adaptive immunity (i.e.
    • B and T cells) differentiate further after exposure to an antigen; they form effector and memory lymphocytes.
    • Effector lymphocytes function to eliminate the antigen, either by releasing antibodies (in the case of B cells), cytotoxic granules (cytotoxic T cells) or by signaling to other cells of the immune system (helper T cells).
  • 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.
    • T cells do not produce antibody molecules.
    • This activation results in the expansion of the antigen-specific lymphocyte pool and the differentiation of these cells into effector and memory cells.
    • Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
  • Lymphoid Tissue

    • Specialized lymphoid tissue supports proliferation and differentiation of lymphocytes.
    • The thymus gland and bone marrow contain primary lymphoid tissue where B and T cells are generated.
    • T cells mature in the thymus, while B cells mature in the bone marrow.
    • T cells born in bone marrow travel to the thymus gland to mature.
    • In addition to supporting B and T lymphocyte activation, other secondary lymphoid organs perform other unique functions, such as the spleen's ability to filter blood and the tonsil's ability to capture antigens in the upper respiratory tract.
  • Lymphocytes

    • A lymphocyte is a type of white blood cell in the vertebrate immune system.
    • A lymphocyte is a type of white blood cell in the immune system, including both the B and T cells of the adaptive immune system and natural killer (NK) cells of the innate immune system .
    • While these are the main categories of T lymphocytes, there are other subtypes within these categories as well as additional categories that are not fully understood.
    • Regulatory B cells (B reg cells) are immunosuppresive B cells that secrete anti-inflammatory cytokines (such as IL-10) to inhibit autoimmune lymphocytes.
    • A scanning electron microscope (SEM) image of a single human lymphocyte.
  • Lymphoid Cells

    • The three major types of lymphocyte are T cells, B cells, and natural killer cells.
    • T and B lymphocytes are the main forces of adaptive immunity, which includes cell-mediated and humoral immunity.
    • Sometimes these lymphocytes react to antigens that aren't harmful (allergy) or will attack antigens expressed from the host's own body (autoimmunity).
    • B cells mature into B lymphocytes in the bone marrow, while T cells migrate to and mature in thymus.
    • The lymphocytes involved in adaptive immunity (B and T cells) differentiate further after exposure to an antigen, which occurs in the lymph nodes during antigen presentation from the dendritic cells.
  • Clonal Selection of Antibody-Producing Cells

    • The clonal selection hypothesis has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens invading the body .
    • Each lymphocyte bears a single type of receptor with a unique specificity (by V(D)J recombination).
    • Those lymphocytes bearing receptors for self molecules will be deleted at an early stage.
    • B cells that have not been activated by antigen are known as naive lymphocytes; those that have met their antigen, become activated, and have differentiated further into fully functional lymphocytes are known as effector B lymphocytes.
    • Clonal selection of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors.
  • Clonal Selection and T-Cell Differentiation

    • Clonal selection means that an antigen is presented to many circulating naive B and (via MHC) T cells, and that the lymphocytes that match the antigen are "selected" to form clones of themselves, both memory and effector.
    • T Cell differentiation happens via the following steps:
    • Cloned daughter cells differentiate into either effector T cells or memory T cells.
    • Cytotoxic effector T cells are finished, but helper T cells continue to differentiate into individual subsets of helper T cells.
    • Clonal selection of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors.
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