PAF is required for inhibition of adhesion by feG. The inclusion of PAF (10-9M) was required to observe an inhibitory effect of feG (10-11M) on the adhesion of peritoneal leukocytes from unsensitized animals to fibrinogen and fibronectin. With extravasated neutrophils feG inhibition of adhesion only occurred in the presence of PAF for fibronectin. Control (black column), feG (open column; 10-11M), PAF (crossed column), and PAF + feG (lined column). Mean ± SEM; p < 0.05; * = less than corresponding controls; n ≥ 4 for each group of cells and substrate.