CD Markers
CD49b
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: CD49
Related: CD49a CD49c CD49d
CD49b
Author: Nat Pernick, M.D.
Topic Completed: 1 December 2010
Minor changes: 2 October 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: CD49
Related: CD49a CD49c CD49d
Table of Contents
Definition / general | Pathophysiology | Uses by pathologists | Positive staining - normal | VideosCite this page: Pernick N. CD49b. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd49b.html. Accessed January 15th, 2021.
Definition / general
- Platelet receptor that mediates adhesion to subendothelial tissue after endothelial damage
- Also called very late antigen (VLA) alpha 2 chain
- Called GP Ia/IIa receptor (integrin alpha2beta1) on platelets
- Associated with neonatal alloimmune thrombocytopenia (CD49b is BRa, Vox Sang 1988;54:101)
- Elevated numbers of peripheral blood CD18(high) CD49b+ T cells are associated with severe uncontrolled asthma (Int Arch Allergy Immunol 2006;140:139)
- CD49b C807T polymorphism is associated with high density of alpha2beta1 receptor on platelets (Arterioscler Thromb Vasc Biol 2005;25:1756); severe retinopathy in patients with diabetes > 25 years (Thromb Haemost 2003;89:142); ischemic strokes in young monozygotic twins (Blood Coagul Fibrinolysis 2003;14:83)
- References: OMIM #192974
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
