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Endothelial Cells

Stem Cell Research

Properties of Cytokines

Cytokines are small proteins that regulate immunity, inflammation, and Hematopoiesis throughout the body. Cytokines are also known by the following names:

  • Lymphokine
  • Monokine
  • Chemokine
  • Interleukin

Cytokines are produced in response to an immune stimulus. All Cytokines have certain properties in common. Cytokines are all small molecular weight Peptides or Glycopeptides. Cytokines are produced by multiple cell types such as:

  • lymphocytes
  • monocytes
  • macrophages
  • mast cells
  • eosinophils
  • endothelial cells

Each individual Cytokine can have multiple functions depending upon the cell that produces it and the pleiotropism (or cell upon which the Cytokine acts). Also, several different Cytokines can have the same biologic function. This is called redundancy. Cytokines can exert their effect on distant cells by using the bloodstream, adjacent cells, or the same cell that produces the Cytokine. These different types of Cytokines are known by the following distinct names:

  • endocrine (act on distant cells)
  • paracrine (act on close cells)
  • autocrine (act on the same cell)

Most Cytokines have the greatest effects in a paracrine or autocrine manner. Cytokines’ major functions appear to involve host defense or maintenance and repair of the blood elements

In most instances, Cytokines are categorized by their major specific functions. Consider the four major categories of Cytokines:

  • Interferons (interfere with virus replication)
  • Interferon alpha (IFNa) (produced by the white blood cells)
  • Interferon beta (IFNb) (produced by fibroblasts)
  • Interferon gamma (IFNg) (produced by activated T cells)