Dictionary > Hemolysin

Hemolysin

Definition
noun, plural: hemolysins
An agent or substance that causes hemolysis, i.e. the lysis of red blood cells resulting in the release of hemoglobin
Supplement
A hemolysin refers to any agent or substance that promotes hemolysis. It may be an exotoxin protein produced by bacteria. It may also be an antibody in which the resulting immune action involves hemolysis. Other possible hemolysins are other immunologic factors, toxins, and enzymes. A hemolysin is capable of causing lysis of the red blood cells resulting in the release of hemoglobin.
A hemolysin produced by bacteria (e.g. Staphyloccus and Streptococcus spp.) is exemplified by streptolysin. Streptococci producing exotoxic streptolysins may be grouped as alpha– or beta-. The alpha-hemolytic streptococci produce hemolysins that can cause incomplete hemolysis whereas the beta-type causes complete hemolysis of red blood cells.
Hemolysis of red blood cells can also be mediated by antibodies. Two possible mechanisms are described: (1) intravascular destruction of erythrocytes by complement lysis and (2) extravascular destruction of erythrocytes by immune cells that recognize antibody and complement bound to the erythrocyte.1
Autoimmune hemolytic anemia is an example of a rare case wherein the action of the antibodies is directed towards own red blood cells. The condition is, thus, characterized by anemia (where there is an insufficient number of erythrocytes to carry oxygen in the bloodstream).
Word origin: Greek haǐma (blood) + lysin
Variant(s):

  • haemolysin (British)

Synonym(s):

  • erythrocytolysin
  • erythrolysin
  • See also:

    Reference(s):

    1 Flegel, W. A. (2015). Pathogenesis and mechanisms of antibody-mediated hemolysis. Transfusion, 55(0), S47–S58. http://doi.org/10.1111/trf.13147


    You will also like...

    Gene Pool and Speciation
    The Gene Pool and Population Genetics

    According to Charles Darwin's theory of natural selection, preferable genes are favored by nature in the gene pool, and ..

    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..

    Early Mammals on Earth
    Early Mammals on Earth

    The Earth's ecosphere was rapidly changing and throwing up a wide range of ecological niches that new adaptive organisms..

    Chromosome Mutations
    Chromosome Mutations

    Mutations can also influence the phenotype of an organism. This tutorial looks at the effects of chromosomal mutations, ..

    Ploidy
    Polyploidy

    Humans are diploid creatures. This means that for every chromosome in the body, there is another one to match it. Howeve..

    Homo Species
    The Homo Species

    The evolution of the species of the genus "Homo" led to the emergence of modern humans. Find out more about human evolut..

    Related Articles...

    No related articles found

    See all Related Topics