CD Markers

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 December 2015, last major update January 2011

Copyright: (c) 2003-2015,, Inc.

PubMed Search: CD46[title]
Cite this page: CD46. website. Accessed October 26th, 2016.
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