dendritic cell

(noun)

Any cell, having branching processes, that forms part of the mammalian immune system.

Related Terms

Examples of dendritic cell in the following topics:

  • Dendritic Cells

    • Dendritic cells are immune cells that function to process antigens and present them to T cells.
    • Immature dendritic cells (e.g.
    • Subsets of dendritic cells can be distinguished by the expression of cell surface markers.
    • Dendritic cells are constantly in communication with other cells in the body.
    • For example, stimulating dendritic cells in vivo with microbial extracts causes the dendritic cells to rapidly begin producing interleukin 12 (IL-12).

  • Cell-Mediated Autoimmune Reactions

    • A normal immune response is assumed to involve B and T cell responses to the same antigen, where B cells recognize conformations on the surface of a molecule for B cells, and T cells recognize pre-processed peptide fragments of proteins for T cells.
    • Together with the concept of T cell-B cell discordance, this idea forms the basis of the hypothesis of self-perpetuating autoreactive B cells.
    • Immune system cells called dendritic cells present antigens to active lymphocytes.
    • Dendritic cells that are defective in apoptosis can lead to inappropriate systemic lymphocyte activation and consequent decline in self-tolerance.
    • HLA-DQ (DQ) is a cell surface receptor type protein found on antigen presenting cells.

  • Tissue Tropism in Animal Viruses

    • Various factors determine the ability of a pathogen to infect a particular cell.
    • For example, viruses must bind to specific cell surface receptors to enter a cell.
    • T helper cells, macrophages or dendritic cells).
    • These receptors are like keys allowing the viral cell to fuse with a cell or attach itself to a cell.
    • Therefore, HIV can enter T cells and macrophages.

  • Type II (Cytotoxic) Reactions

    • These cells are recognized by macrophages or dendritic cells, which act as antigen-presenting cells.
    • This causes a B cell response, wherein antibodies are produced against the foreign antigen.
    • These channels disrupt the phospholipid bilayer of target cells, leading to cell lysis and death.
    • Here, cells exhibiting the foreign antigen are tagged with antibodies (IgG or IgM).
    • These tagged cells are then recognised by natural killer (NK) cells and macrophages (recognised via IgG bound (via the Fc region) to the effector cell surface receptor, CD16 (FcγRIII)), which in turn kill these tagged cells.

  • Cells and Organs of the Immune System

    • The thymus "educates" T cells and provides an inductive environment for the development of T cells from hematopoietic progenitor cells.
    • The lymphatic system has multiple interrelated functions including the transportation of white blood cells to and from the lymph nodes into the bones, and the transportation of antigen-presenting cells (such as dendritic cells) to the lymph nodes where an immune response is stimulated.
    • Dendritic cells are phagocytes in tissues that are in contact with the external environment, and are located mainly in the skin, nose, lungs, stomach, and intestines.
    • Natural killer cells are leukocytes that attack and destroy tumor cells, or cells that have been infected by viruses.
    • B cells and T cells are the major types of lymphocytes and are derived from hematopoietic stem cells in the bone marrow.

  • Phagocyte Migration and Phagocytosis

    • Phagocytosis is the engulfment of foreign material in a body by a specialized cell type.
    • Phagocytosis is the process by which a cell takes in particles such as bacteria, parasites, dead host cells, and cellular and foreign debris.
    • Dendritic cells and macrophages, on the other hand, are not so fast, and phagocytosis can take many hours in these cells.
    • In this semi-resting state, they clear away dead host cells and other non-infectious debris and rarely take part in antigen presentation.
    • Other signals called vasodilators loosen the junctions connecting endothelial cells, allowing the phagocytes to pass through the wall.

  • Immunotherapy for Cancer

    • Cell-based immunotherapy is another major entity of cancer immunotherapy.
    • This involves immune cells such as the natural killer cells (NK cells), lymphokine-activated killer cells (LAK cells), cytotoxic T lymphocytes (CTLs), and dendritic cells (DC).
    • Adoptive cell-based immunotherapy involves isolating either allogenic or autologous immune cells, enriching them outside the body, and transfusing them back to the patient.
    • The injected immune cells are highly cytotoxic to the cancer cells and so help to fight them.
    • Topical immunotherapy utilizes an immune enhancement cream (imiquimod), which is an interferon producer, causing the patient's own killer T cells to destroy warts, actinic keratoses, basal cell carcinoma, squamous cell carcinoma, cutaneous T cell lymphoma, and superficial spreading melanoma.

  • Replicative Cycle of HIV

    • HIV can infect dendritic cells (DCs).
    • HIV enters macrophages and T cells by the adsorption of glycoproteins on its surface to receptors on the target cell.
    • This is followed by fusion of the viral envelope with the cell membrane and the release of the HIV capsid into the cell.
    • These are transported to the plasma membrane of the host cell where gp41 anchors gp120 to the membrane of the infected cell.
    • The mature virion is then able to infect another cell.

  • Double-Stranded DNA Viruses: Adenoviruses

    • The virion also has unique "spike" or fiber associated with each penton base of the capsid that aids in attachment to the host cell via host cell surface receptors .
    • Entry of adenoviruses into the host cell involves two sets of interactions between the virus and the host cell.
    • First, entry into the host cell is initiated by the knob domain of the fiber protein binding to a host cell receptor, either CD46 for the group B human adenovirus serotypes, or the coxsackievirus adenovirus receptor for all other serotypes.
    • Once the viral components have successfully been replicated, the virus is assembled into its protein shells and released from the cell as a result of virally induced cell lysis.
    • Adenovirus dodecahedron serves as a potent delivery platform for foreign antigens to human myeloid dendritic cells (MDC), and is efficiently presented by MDC to M1-specific CD8+ T lymphocytes.

  • Other Infectious Eye Diseases

    • This classic herpetic lesion consists of a linear branching corneal ulcer (dendritic ulcer).
    • Acanthamoeba is a microscopic, free-living ameba (single-celled living organism) commonly found in the environment that can cause rare, but severe, eye illness.
    • A single-celled parasite called Toxoplasma gondii causes a disease known as toxoplasmosis.
    • Summarize the various types of herpes simplex keratitis: dendritic ulcer (epithelial keratitis) and disciform keratitis (stromal keratitis)