A novel monoclonal antibody mNI‐58A against the α‐chain of leukocyte function‐associated antigen‐1 (LFA‐1) blocks the homotypic cell aggregation and actively regulates morphological changes in the ohorbol myristate acetate (PMA)‐activated human monocyte‐like cell line, U937

Publisher Website
Google Scholar
Abstract
A monoclonal antibody (mAb), designated mNI-58A, was produced by immunizing mice with the lipopolysaccharide (LPS)-stimulated monocyte-like cell line, U937. The antigen defined by mNI-58A was widely expressed on various lymphoid cells and all cell lines examined except the erythroid cell line, K562. When the reactive patterns between mNI-58A and the mAbs to various human differentiation antigens (CD11a, CD11b, CD11c, CD14, CD16, CD18, CD23, CD28, CD29, CD31, CD43, CD44, CD45RA, CD50, CD54, CD58, CD80, CD 102, CD 106, HLA-class I and -class II antigen) were compared, that of mNI-58A was found to be similar to those of the leukocyte function-associated antigen-1 (LFA-1) mAbs. Using a competitive immunofluorescence binding assay it was found that the preincubation with one of the CD11a mAbs, 2F12 completely blocked the subsequent binding of mNI-58A. mNI-58A prevented the homotypic cell aggregation of the phorbol myristate acetate (PMA)-activated U937 cells (referred to as PMA-U937) and PMA-activated Epstein-Barr virus (EBV)-transformed B cell lines, B-85 and Mann. mNI-58A markedly induced the spread formation of the PMA-U937 cells following this blocking of the homotypic cell aggregation, whereas 2F12 did not under the same condition. The spread formation induced by mNI-58A was completely blocked by cytochalasin B (CyB), cytochalasin D (CyD), cycloheximide (CHX) or protein kinase C inhibitors, sphingosine and H-7. The U937 cells markedly adhered to the tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs) and also to the extracellular matrix protein, fibronectin, but mNI-58 A did not enhance or block these adhesion processes. mNI-58A precipitated two glycoproteins with molecular weight 180 kDa and 95 kDa as determined by SDS-PAGE analysis, which were identical to the LFA-α (CD 11 a) and β (CD 18) chains of leukocyte integrin precipitated by the CD 11 a mAbs, respectively. Sequential immunoprecipitation studies using the CD1 la mAb (2F12) also indicate that mNI-58 A recognizes an epitope on the α-chain of the LFA-1 motecule. The ability of mNI-58 A to block the PMA-U937 cells and to induce the spread formation of these cells suggests that mNI-58A is a novel mAb reacting with an epitope on the α-chain of LFA-1 different from those recognized with the existing CD1 la mAbs.

This publication has 55 references indexed in Scilit: