ROLE OF ADHESION GLYCOPROTEINS CD18 AND INTERCELLULAR-ADHESION MOLECULE-1 IN COMPLEMENT-MEDIATED REACTIONS OF RABBIT SKIN

1 The role of the adhesion glycoproteins CD18 and intercellular adhesi on molecule-1 (ICAM-1) in inflammatory responses produced during a rev ersed passive Arthus (RPA) reaction and induced by zymosan and zymosan -activated plasma (ZAP) were studied in rabbit skin. 2 Oedema formatio n and haemorrhage were quantified by measuring accumulation of I-125-a lbumin and In-111-labelled red blood cells (In-111-RBC) respectively. 3 Monoclonal antibody (mAb) R15.7 (anti-CD18), administered intravenou sly, abolished accumulation of I-125-albumin and In-111-RBC in dermal RPA reactions and in response to locally injected zymosan and ZAP. 4 W hen administered intravenously, the mAb RR1/1 (anti-ICAM-1) suppressed I-125-albumin and In-111-RBC accumulation in dermal RPA reactions and at sites treated with zymosan and ZAP. 5 Oedema formation in response to platelet-activating factor (PAF) and bradykinin (BK) either in the presence or absence of prostaglandin E(2) (PGE(2)) were not affected by mAb R15.7 or by mAb RR1/1.1.1. 6 We conclude that oedema formation and haemorrhage associated with RPA reactions and in responses to zymo san and ZAP are completely CD18-dependent, and are mediated, at least in part, via ICAM-1. Responses to the neutrophil-independent oedema fo rming mediators, PAF and BK are not dependent upon CD18 or (ICAM-1)