Anti-Human CD11b (activation epitope) FITC

Description: The CBRM1/5 monoclonal antibody reacts with an activation-specific epitope of human Mac-1. CBRM1/5 binds a subset of Mac-1 molecules on neutrophils and monocytes after stimulation with chemoattractants or phorbol esters but does not recognize Mac-1 on resting myeloid cells. Through interactions with its ligands, Mac-1 participates in adhesive cell interactions. The epitope recognized by this mAb localizes to the I domain on the α chain of Mac-1 very close to the ligand binding site in a region that is widely exposed. CBRM1/5 blocks Mac-1 dependent adhesion to fibrinogen and ICAM-1 and inhibits chemoattractant-stimulated adhesion of eosinophils to the Intercellular Adhesion Molecule-1 (ICAM-1). It should be noted that low level activation may occur during processing of freshly drawn blood. Therefore the CBRM1.5 antibody may exhibit some binding to Mac-1 in these unstimulated samples. However, higher levels of Mac-1 expression are observed in activated samples when compared to unstimulated cells.

References: Oxvig C, Lu C, Springer TA. Conformational changes in tertiary structure near the ligand binding site of an integrin I domain. Proc Natl Acad Sci U S A. 1999 Mar 2;96(5):2215-20.

Weber C, Kitayama J, Springer TA. Differential regulation of beta 1 and beta 2 integrin avidity by chemoattractants in eosinophils Proc Natl Acad Sci U S A. 1996 Oct 1;93(20):10939-44.

Diamond MS, Springer TA. A subpopulation of Mac-1 (CD11b/CD18) molecules mediates neutrophil adhesion to ICAM-1 and fibrinogen. J Cell Biol. 1993 Jan;120(2):545-56.