Integrin alpha-4 beta-1 (VLA-4) receptor – Vascular cell adhesion molecule 1 (VCAM-1) (VLA-4 – VCAM-1)

The VLA-4 – VCAM-1 interaction is a critical mediator of leukocyte trafficking and adhesion to the vascular endothelium (PubMed: 10477543). VLA-4 (Very Late Antigen-4), also known as integrin alpha-4 beta-1, is a heterodimeric protein expressed on the surface of most leukocytes, including T and B lymphocytes, monocytes, and eosinophils (UniProt: P13612). Its primary ligand, Vascular Cell Adhesion Molecule-1 (VCAM-1), is a member of the immunoglobulin superfamily that is upregulated on endothelial cells during inflammatory responses (PubMed: 1711449). This interaction facilitates the firm adhesion and subsequent transendothelial migration of leukocytes into inflamed tissues, such as the central nervous system in multiple sclerosis or the intestinal mucosa in inflammatory bowel disease (StatPearls: NBK537265). Therapeutic targeting of this axis, most notably with the monoclonal antibody Natalizumab, aims to block this recruitment process to reduce tissue damage (PubChem: CID 135311935). However, long-term inhibition of this pathway is associated with significant risks, particularly the reactivation of the JC virus leading to Progressive Multifocal Leukoencephalopathy (PML), due to impaired immune surveillance in the brain (NIH: PMC3136031).

Other names

CD49d/CD29 – CD106 interactionVery Late Antigen-4 – Vascular Cell Adhesion Molecule-1alpha4beta1 – VCAM1 axisVLA-4/VCAM-1 interaction

Therapeutic agents targeting this interaction primarily function as antagonists that bind to the alpha-4 subunit (CD49d) of the VLA-4 integrin. This binding sterically inhibits the docking of VLA-4 to its ligand, VCAM-1, on the vascular endothelium, thereby blocking the extravasation of inflammatory leukocytes across the blood-brain barrier or into the intestinal mucosa (PubMed: 15548772).