Role of the LFA-1 adhesion glycoprotein in neutrophil adhesion to endothelium and plastic surfaces

Neutrophil adherence to endothelium is known to be mediated, at least in part, by adhesion molecules such as LFA-1. Deficiency of these adhesion molecules leads to recurrent infection and early death from infection. As screening for defects of these adhesion glycoproteins is often performed by the ability of neutrophils to adhere to plastic plates, in this study a comparison of neutrophil adherence by the CD18/CD11a (LFA-1) mechanism to endothelium and plastic surfaces was examined. Baseline neutrophil adherence was two-fold higher to plastic than to endothelium (17% ± 9 for plastic, 8% ± 5 for endothelium). Baseline adherence to endothelium was partially inhibitable by anti-LFA-1 antibodies, whereas no inhibition of adherence occurred on plastic. Neutrophil stimulants increased adherence to both surfaces, although only on endothelium was this increase attributable to the LFA-1 mechanism. IL-1 increased adherence to endothelium, but had no effect on plastic. We conclude that adherence of neutrophils to plastic surfaces probably represents overall activation status through undefined mechanisms, is not by LFA-1 receptor ligand interactions, and is therefore a non-physiological phenomenon. Endothelial receptors are pivotal in neutrophil adherence. It would be more appropriate to screen leucocytes for leucocyte adhesion deficiency by assaying for specific receptor occupancy with monoclonal antibodies, rather than an assay such as adhesion to plastic where the adhesion ligand is non specific.