1eye wrote:The other thing I was thinking is, what if what they were doing was being propelled along by some kind of force from inside the vessel, maybe the same thing that make them stay on the vessel? They are single cells, which cannot think or feel. What motivates them? Perhaps it is charge. Perhaps it is magnetism. Something moving along with the blood. I have read about "affinity" but how does it physically work? How do cells follow sources (trails?) of molecules? They have no brains. Without a brain or eyes, how does any single-celled organism find food? Or, in the case of immune cells, find invaders to attack? I bet they are following charge, which changes with blood velocity and direction, and changes with the presence of unwanted visitors.
Any cell biologists care to comment?
That might explain why immune cells might follow myelin, if it's carrying electricity makes them locomote, and electrical transitions make them try to squirt through, which results instead in demyelination.
Tysabri prescribing information wrote:Natalizumab binds to the alpha-4-subunit of alpha-4-beta-1 and alpha-4-beta-7 integrins expressed on the surface of all leukocytes except neutrophils, and inhibits the alpha-4-mediated adhesion of leukocytes to their counter-receptor(s). The receptors for the alpha-4 family of integrins include vascular cell adhesion molecule-1 (VCAM-1), which is expressed on activated vascular endothelium, and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) present on vascular endothelial cells of the gastrointestinal tract. Disruption of these molecular interactions prevents transmigration of leukocytes across the endothelium into inflamed parenchymal tissue. In vitro, anti-alpha-4-integrin antibodies also block alpha-4-mediated cell binding to ligands such as osteopontin and an alternatively spliced domain of fibronectin, connecting segment-1 (CS-1). In vivo, natalizumab may further act to inhibit the interaction of alpha-4-expressing leukocytes with their ligand(s) in the extracellular matrix and on parenchymal cells, thereby inhibiting further recruitment and inflammatory activity of activated immune cells.
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