CD Markers
CD49



Topic Completed: 1 December 2010

Minor changes: 14 May 2021

Copyright: 2002-2022, PathologyOutlines.com, Inc.

PubMed Search: CD49

Nat Pernick, M.D.
Page views in 2021: 613
Page views in 2022 to date: 45
Table of Contents
CD49a | CD49b | CD49c | CD49d | CD49e | CD49f
Cite this page: Pernick N. CD49. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd49a.html. Accessed January 21st, 2022.
CD49a

Definition / general
  • Integrin alpha 1 chain, which combines with beta1 subunit (CD29) to form a receptor for collagen and laminin
  • Also called very late antigen (VLA) alpha 1 chain, integrin alpha 1 chain and ITGA1
  • Mesenchymal stem cells are selected from bone marrow by CD49+ with flow cytometry (Br J Haematol 2003;122:506, J Mol Histol 2007;38:449)
  • Reference: OMIM #192968

Pathophysiology
  • Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain; a given chain may combine with multiple partners resulting in different integrins
  • Very late activation proteins (VLA) are a family of integrins originally identified on activated human T cells, later on fibroblasts and platelets
  • CD49a combines with beta1 subunit (CD29) to form a receptor for collagen and laminin; this receptor may also be involved in cell-cell adhesion and play a role in inflammation and fibrosis
  • CD49a contributes to beta cell functions important for pancreatic islet morphogenesis and glucose homeostasis (J Biol Chem 2004;279:53762)

Uses by pathologists
  • No significant clinical use by pathologists

Positive staining - normal
  • Activated B and T cells, monocytes, fibroblasts, platelets, endothelial cells and smooth muscle cells
CD49b

Definition / general

Pathophysiology
  • Receptor for laminin, collagen, fibronectin and E-cadherin
  • Responsible for platelet adhesion to subendothelial tissue; after endothelial damage, circulating platelets via platelet surface GP Ib-IX-V complex contact subendothelial vWF bound to collagen; this initial contact slows down the platelets, allowing platelet CD49b to bind to endothelial collagen; this stops the platelets and contributes to their activation and aggregation (Blood 2005;105:1986)
  • CD49b mediates disassembly of actin cytoskeleton stress fibers and focal adhesions, leading to block of endothelial cell migration and angiogenesis (J Cell Biol 2004;166:97)
  • May be a immunodominant minor histocompatibility antigen (Blood 1998;92:2169)

Uses by pathologists
  • No significant clinical use by pathologists

Positive staining - normal
  • Platelets, activated B & T cells, monocytes, megakaryocytes and NK cells (most)

Videos

Platelet adhesion and aggregation

CD49c

Definition / general
  • Major receptor for laminin; also a receptor for collagen, fibronectin and thrombospondin
  • Also called very late antigen (VLA) alpha 3 chain (VLA-3), ITGA3
  • Common integrin is alpha3beta1, which is CD49c and CD29
  • Has 2 isoforms produced by alternate splicing: alpha-3A and alpha-3B
  • Tumor cell alpha3beta1 binds to exposed basement membrane on pulmonary vessels to cause tumor cell arrest and early colony formation (J Cell Biol 2004;164:935)
  • May play a role in peritoneal dissemination of gastric carcinoma (Cancer Res 2004;64:6065)
  • May mediate invasion of melanoma cells (Clin Exp Metastasis 2002;19:127)
  • Reference: OMIM #605025

Pathophysiology

Uses by pathologists
  • No significant clinical use by pathologists

Positive staining - normal

Negative staining
  • Platelets
CD49d

Definition / general
  • Receptor for fibronectin, thrombospondin and VCAM1 / CD106
  • Also called very late antigen (VLA) alpha 4 chain (VLA4), ITGA4
  • Relevant to tumor progression and metastasis
  • Increased expression during relapse in multiple sclerosis (J Neuroimmunol 2005;166:189)
    • Treatment with alpha4 integrin antagonist natalizumab led to fewer inflammatory brain lesions and fewer relapses in patients with relapsing multiple sclerosis (N Engl J Med 2003;348:15)
    • Although it is also associated with progressive multifocal leukoencephalopathy (Neurol Res 2006;28:299)
  • Reference: OMIM #192975

Pathophysiology
  • Combines with CD29 to form alpha4 beta1 integrin
  • Has role in cell-cell interactions, cell adhesion to the extracellular matrix
  • Integrins alpha4beta1 and alpha4beta7 are receptors for fibronectin
  • Integrin alpha4beta1 is also a receptor for VCAM1 / CD106, MAdCAM1 and thrombospondin
  • Avidity (binding strength) of cells expressing alpha4beta1 integrin can be rapidly changed by chemokines and chemoattractants
  • Integrin anchorage to cytoskeleton enhances the mechanical stability of its adhesive bonds under strain and promotes its ability to mediate leukocyte adhesion under physiological shear stress conditions (J Cell Biol 2005;171:1073)
  • Promotes (a) lymphocyte migration into tissue by strengthening lymphocyte adhesion to endothelial cells, (b) rolling of T cells in vascular lumen on VCAM-1 of endothelium, (c) homing of T cell subsets to Peyer's patches, (d) differentiation of hematopoietic precursor cells by adhesion to bone marrow stromal cells

Uses by pathologists

Positive staining - normal
  • Macrophages, T and B cells, eosinophils, basophils, NK cells, dendritic cells, Langerhans cells, myeloid cells, erythrocyte precursors and thymocytes
  • Also basal epidermal layer

Positive staining - disease
  • Found in suprabasal skin during wound healing and psoriasis
  • Melanoma, ALL and AML

Negative staining
  • Erythrocytes, platelets and neutrophils
CD49e

Definition / general
  • Fibronectin and fibrinogen receptor

Terminology
  • Also called very late antigen (VLA) alpha 5 chain (VLA5), ITGA5, fibronectin receptor (FNRA)

Physiology
  • Recognizes the sequence R-G-D in fibronectin and fibrinogen, mediating its adhesion function

Clinical features

Uses by pathologists
  • No significant clinical use by pathologists

Immunofluorescence images

Contributed by Vincent Achard, M.D., Ph.D.
Peripheral blood monocytes and platelets (green is positive)

Peripheral blood monocytes and platelets (green is positive)

Negative control

Negative control



Positive staining - normal
  • T cells, early and activated B cells, platelets, monocytes, neutrophils

Additional references
CD49f

Definition / general
  • Forms laminin and thrombospondin receptors

Terminology
  • Also called very late antigen (VLA) alpha 6 chain (VLA6), ITGA6

Physiology
  • Forms laminin receptor on platelets (with CD29 / alpha6beta1) and on epithelial cells (with CD104 / alpha6beta4); alpha6beta1 is also part of the thrombospondin receptor (J Biol Chem 2003;278:40679)
  • Important for formation of hemidesmosomes on stratified squamous and transitional epithelia

Clinical features

Uses by pathologists
  • No significant clinical use by pathologists

Positive staining - normal
  • Epithelial cells, memory T cells, monocytes, platelets, megakaryocytes, thymocytes

Additional references
Back to top
Image 01 Image 02