LFA-1 (CD11a/CD18) and ICAM-1 (CD54) Antibodies Attenuate Superoxide Anion Release from Polymorphonuclear Leukocytes in Rats with Experimental Acute Pancreatitis

The inhibitive effects of anti-CD11a/CD18 (LFA-1) and anti-CD54 (ICAM-1) antibodies on the generation of superoxide anion (O2-) by polymorphonuclear leukocytes (PMNs) was elucidated in rats induced with experimental acute pancreatitis. We investigated the generation of O2- by PMNs in two protocols: in the first, we measured the active oxygen-producing ability of PMNs isolated from blood in normal rats; in the second, we measured it from blood, peritoneal cavity, and bronchial alveolar lavage fluid in rats 3 h after the induction of pancreatitis. In normal rats, although LFA-1 antibody attenuated the generation of O2-, ICAM-1 antibody did not. However, in pancreatitis rats, both LFA-1 and ICAM-1 antibodies reduced the generation of O2- by PMNs isolated from blood and the peritoneal cavity. These results showed not only that both LFA-1 and ICAM-1 antibodies have a protective effect on the generation of O2-, but also that LFA-1 has a direct inhibitive effect on the generation of O2- by PMNs in this model. Furthermore, histological studies showed there to be less neutrophil accumulation in the lungs of LFA-1- and ICAM-1-treated animals compared to control animals.