Integrin alpha-M beta-2 (Mac-1) – Intercellular adhesion molecule 1 (ICAM-1) interaction axis (Mac-1 – ICAM-1 axis)

The Leukocyte Mac-1 – ICAM-1 interaction axis is a critical molecular pathway mediating the recruitment and firm adhesion of leukocytes to the vascular endothelium during inflammatory responses [2, 4]. Mac-1, a heterodimeric integrin composed of alpha-M (CD11b) and beta-2 (CD18) subunits, is primarily expressed on the surface of myeloid cells such as neutrophils, monocytes, and macrophages [4, 7]. It interacts with Intercellular Adhesion Molecule 1 (ICAM-1), a member of the immunoglobulin superfamily expressed on endothelial and epithelial cells, to facilitate leukocyte crawling and transendothelial migration (diapedesis) into tissues [2, 8]. This interaction is not only essential for normal immune surveillance and host defense but is also a key driver of pathological inflammation in diseases such as rheumatoid arthritis, inflammatory bowel disease, and atherosclerosis [5, 17, 18]. Therapeutic strategies targeting this axis aim to disrupt the binding between Mac-1 and ICAM-1 to reduce excessive leukocyte infiltration and subsequent tissue damage [1, 5]. Pharmacological agents include monoclonal antibodies like Enlimomab, small molecule allosteric modulators like Leukaderin-1, and antisense oligonucleotides like Alicaforsen that either block the binding site or reduce the expression of the components [5, 8, 14]. However, because Mac-1 is also involved in the phagocytosis of complement-opsonized pathogens (as Complement Receptor 3), its inhibition carries significant safety concerns, including an increased risk of bacterial and fungal infections [4, 5]. Clinical monitoring often involves measuring soluble ICAM-1 (sICAM-1) levels or the expression of activation-specific epitopes on leukocytes to assess treatment efficacy and safety [6, 15].

Other names

CD11b/CD18 – CD54 interactionMacrophage-1 antigen – Intercellular adhesion molecule 1 axisCR3 – ICAM-1 interactionIntegrin alpha-M beta-2 – ICAM-1 axisLeukocyte integrin – Endothelial adhesion molecule interaction

Inhibition of protein-protein interaction between leukocyte integrins and endothelial adhesion molecules to prevent leukocyte recruitment, firm adhesion, and extravasation into inflamed tissues.