CD Markers

Topic Completed: 1 July 2013

Minor changes: 1 October 2020

Copyright: 2002-2021,, Inc.

Related: CD1aCD1bCD1cCD1dCD1e

Nat Pernick, M.D.
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Cite this page: Pernick N. CD1. website. Accessed May 8th, 2021.
Definition / general
  • Family of nonpolymorphic MHC class I-like glycoproteins on surface of various antigen presenting cells; member of immunoglobulin superfamily
  • Mediate presentation of endogenous and foreign lipids (including bacterial lipid antigens) on cell surface for recognition by T cell receptors
  • To sample a diverse antigen pool, CD1 proteins are repeatedly internalized and recycled; this may be assisted by lipid transfer proteins such as saposins (J Biol Chem 2013;288:19528, Proc Natl Acad Sci USA 2012;109:4357)
  • May also mediate thymic T cell development
  • Has 5 different subsets (CD1a, CD1b, CD1c, CD1d, CD1e), all noncovalently associated with beta 2 microglobulin, all on #1q22-23 (non-MHC linked)
  • The different CD1 forms bind to different types of lipid antigen based on differences in their antigen binding grooves (Nat Rev Immunol 2005;5:387)
  • Separated into 2 groups based on sequence homology: group 1 (CD1a, CD1b, CD1c) - present in humans, some other mammals, not in mouse or rat; group 2 (CD1d) - present in all mammals studied (Curr Pharm Des 2009;15:3311); CD1e is an intermediate form, expressed intracellularly (J Biol Chem 2000;275:37757)
  • Cellular infection with Mycobacteria tuberculosis or exposure to mycobacterial cell wall products converts CD1- myeloid precursors into competent CD1+ antigen presenting cells (J Immunol 2005;175:1758); however M. tuberculosis possesses a successful tactic based, at least in part, on CD1 downregulation to evade CD1 dependent immunity (Clin Dev Immunol 2011;2011:790460)
  • Pollen lipids are also recognized as antigens by T cells via CD1 dependent pathway (J Exp Med 2005;202:295)
Clinical features
Uses by pathologists
  • CD1a is used to diagnose Langerhans cell histiocytosis and to exclude other entities that are CD1a negative
Microscopic (histologic) images

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Primary and metastatic melanoma

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Langerhans cells of anal mucosa

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