CD Markers

Topic Completed: 1 January 2011

Minor changes: 2 October 2020

Copyright: 2003-2021,, Inc.

PubMed Search: CD46[title]

Nat Pernick, M.D.
Page views in 2020: 70
Page views in 2021 to date: 4
Cite this page: Pernick N. CD46. website. Accessed January 16th, 2021.
Definition / general
  • Antigen which helps downregulate the immune system
  • Also called membrane cofactor protein (MCP), Trophoblast leukocyte common antigen
  • Has multiple isoforms, but unlike CD45, they don’t appear to have clinical significance
  • Cofactor for proteolytic cleavage of C3b and C4b by factor I (J Immunol 2002;168:6298), which prevents inappropriate complement activation, especially via alternative pathway, by limiting formation and function of C3 convertases
  • Induces regulatory T cells (Nature 2003;421:388), which suppress immune function by secreting IL-10, and may prevent autoimmunity; various pathogens (see below) appear to exploit this property by binding to CD46 to induce an immunosuppressive phenotype
Clinical features
Uses by pathologists
  • No significant clinical use by pathologists
Positive staining - normal
  • All cells except erythrocytes and some bone marrow cells
Negative staining
  • Red blood cells
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