Dictionary > Exogenous pyrogen

Exogenous pyrogen

Definition
noun, plural: exogenous pyrogen
A type of pyrogen that is of microbial origin, such as the lipopolysaccharide in the cell wall of phagocytosed gram-negative bacteria
Supplement
Pyrogens are substances that induce fever. In the presence of an infectious agent, such as bacteria, prions, viruses, viroids, etc., the immune response of the body is to inhibit their growth and eliminate them. Fever usually occurs during an infection as part of the body’s natural defense against these invading agents. The hypothalamus regulates the temperature of the body to maintain a temperature within the normal range. It makes the body respond to cold by generating heat such as through shivering (i.e. skeletal muscle contraction).
Pyrogens may be exogenous or endogenous. Exogenous pyrogens are of microbial origin. An example of exogenous pyrogen is the lipopolysaccharide, which is a component of the cell wall of certain gram-negative bacteria. When it binds to a lipopolysaccharide-binding protein of the immune cell, it forms a complex that binds in turn to a CD14 receptor of a macrophage. The latter will then be
stimulated to release endogenous pyrogens such as interleukin-6, interleukin-1, tumour necrosis factor, interferon-alpha, gp130 Receptor Ligands, etc. 1
Compare:

See also:

  • pyrogen
  • fever
  • hypothalamus
  • cytokine
  • Reference(s):

    1 Dinarello, C. A. Cytokines as Endogenous Pyrogens. The Journal of Infectious Disease 1999 179: S294-S304.


    You will also like...

    running freshwater community
    Running Water Freshwater Community Factors

    This tutorial noted some of the physical and chemical factors that provide the framework of a running water community in..

    Human Reproduction
    Human Reproduction

    Humans are capable of only one mode of reproduction, i.e. sexual reproduction. Haploid sex cells (gametes) are produced ..

    Schematic diagram of bacterial lactose operon
    Gene Action – Operon Hypothesis

    Learn how the way genes control and determine every aspect of the body. This lesson uses lac operon as an example. ..

    ..

    Schematic diagram of DNA replication
    DNA Structure & DNA Replication

    DNA is a double helix structure comprised of nucleotides. A nucleotide, in turn, is made up of phosphate molecule, deoxy..

    Ecological Research Measuring & Analysis
    Ecological Research: Measuring & Analysis

    This lesson is about the methods used for ecological research, such as quadrat and transect sampling, canopy fogging, an..

    Plant biology
    Plant Biology

    Plantlife can be studied at a variety of levels, from the molecular, genetic and biochemical level through organelles, c..

    Related Articles...

    No related articles found

    See all Related Topics