KIM185, A MONOCLONAL-ANTIBODY TO CD18 WHICH INDUCES A CHANGE IN THE CONFORMATION OF CD18 AND PROMOTES BOTH LFA-1-DEPENDENT AND CR3-DEPENDENT ADHESION

Unactivated peripheral blood leukocytes show little tendency to bind to other cells or matrix components, whilst, in the presence of inflammatory mediators, adhesive interactions can rapidly increase. The Leu-CAM (beta2 integrin) family of adhesion molecules have been shown to mediate a variety of these induced adhesion events. Here we describe a monoclonal antibody against CD18, KIM185, which stimulates JY cell homotypic aggregation by a CD11a pathway as well as inducing the adherence ot neutrophils to protein-coated plastic by a CD11b-dependent mechanism. The antibody recognizes an epitope distinct from the previously described KIM127 antibody and evidence is presented that the binding of KIM185 can cause a change in the conformation of the CD18 molecule.