ICAM-1-CD18 interaction mediates neutrophil cytotoxicity through protease release.
Interaction of the beta2-integrin complex on the polymorphonuclear neutrophil (PMN) with intercellular adhesion molecule-1 (ICAM-1) has been implicated in PMN-mediated cytotoxicity. This study examined interaction of the CD11a, CD11b, and CD18 subunits of the beta2-integrin with ICAM-1, transfected into Chinese hamster ovarian (CHO) cells to avoid effects of other adhesion molecules. Incubation of quiescent PMNs with wild-type and ICAM-1-transfected CHO cells produced nominal cell lysis. Similarly, when phorbol myristate acetate (PMA)-activated PMNs were incubated with wild-type CHO cells, minimal cytotoxicity was produced. However, when ICAM-1-transfected CHO cells were incubated with PMA-activated PMNs, 40% cell lysis occurred. Blockade with a monoclonal antibody (MAb) to ICAM-1 or MAbs to CD11a, CD11b, or CD18 reduced PMN-mediated cytotoxicity to baseline. To examine the role of adhesion in cytotoxicity, we studied beta2-integrin-mediated PMN adhesion to ICAM-1-transfected CHO cells and found that MAbs for CD11a, CD11b, and CD18 all abrogated PMN cytotoxicity despite disparate effects on adhesion. To assess the role of CD18, beta2-integrin subunits were cross-linked, and CD18 alone mediated protease release. Moreover, ICAM-1 was immunoprecipitated from transfected CHO cells and incubated with PMNs. This soluble ICAM-1 provoked elastase release, similar to PMA, which could be inhibited by MAbs to CD18 but not MAbs to other beta2-integrin subunits. In addition, coincubation with protease inhibitors eglin C and AAPVCK reduced PMN-mediated cytotoxicity to control levels. Finally, ICAM-1-transfected CHO cells were exposed to activated PMNs from a patient with chronic granulomatous disease that caused significant cell lysis, equivalent to that of PMNs from normal donors. Collectively, these data suggest that ICAM-1 provokes PMN-mediated cytotoxicity via CD18-mediated protease release.
Barnett
C C
CC
Department of Surgery, Denver Health Medical Center and University of Colorado Health Sciences Center, Denver, Colorado 80204, USA.
Moore
E E
EE
Mierau
G W
GW
Partrick
D A
DA
Biffl
W L
WL
Elzi
D J
DJ
Silliman
C C
CC
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D018845:CD11 Antigens / Q000276:immunology / Q000502:physiology; D018821:CD18 Antigens / Q000276:immunology / Q000502:physiology*; D016466:CHO Cells; D002448:Cell Adhesion; D016923:Cell Death; D006224:Cricetinae; D003432:Cross-Linking Reagents; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000502:physiology*; D008854:Microscopy, Electron; D009504:Neutrophils / Q000201:enzymology / Q000502:physiology*; D011480:Protease Inhibitors / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D000911:Antibodies, Monoclonal; D018845:CD11 Antigens; D018821:CD18 Antigens; D003432:Cross-Linking Reagents; D011480:Protease Inhibitors; D013481:Superoxides; D018799:Intercellular Adhesion Molecule-1; D010450:Endopeptidases; D013755:Tetradecanoylphorbol Acetate