Leukocyte chemotaxis and adhesion molecule pathways

Leukocyte chemotaxis and adhesion molecule pathways represent the multi-step biological process, often called the leukocyte adhesion cascade, that enables immune cells to exit the bloodstream and enter tissues. This cascade involves a series of sequential interactions: selectin-mediated rolling, chemokine-triggered activation, integrin-mediated firm adhesion, and finally, transendothelial migration (diapedesis). Key molecular components include selectins (L, E, and P), integrins (such as LFA-1 and VLA-4), and their endothelial ligands (ICAM-1, VCAM-1, and MAdCAM-1), alongside various chemokines and their G protein-coupled receptors. These pathways are fundamental to the immune response but are frequently dysregulated in chronic inflammatory and autoimmune diseases like multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis. Consequently, they are major therapeutic targets, with drugs like natalizumab and vedolizumab designed to block specific adhesion molecules to prevent pathological tissue infiltration. While highly effective in reducing inflammation, targeting these pathways can lead to significant safety concerns, including an increased risk of opportunistic infections due to impaired immune surveillance.

Other names

Leukocyte adhesion cascadeLeukocyte recruitment pathwayLeukocyte traffickingLeukocyte extravasationLeukocyte-endothelial cell interaction pathway

Inhibition of leukocyte-endothelial cell interactions by blocking adhesion molecules (integrins, selectins) or their ligands (ICAMs, VCAMs), and antagonism of chemokine or S1P receptors to prevent directed migration and tissue infiltration.