Inhibition of leukocyte attachment to IL-1β-activated glEND.2 cells by antileukoproteinase in vitro. The adherence of human granulocytes to layers of glEND.2 cells was assessed microscopically. The quantitative measure for leukocytes adhering to the glEND.2 cells under the respective incubation conditions is expressed as a percentage of the positive control, which is the mean number of adherent cells to IL-1β-activated endothelium in medium (+IL-1β control; stimulation with 20 ng/ml IL-1β for 4 hours). The percentages of adherent leukocytes to glEND.2 cells were derived from eight independent experiments and are expressed as means and SEM for the following experimental conditions: no stimulus (- IL-1β control), IL-1β stimulation after pretreatment with either antileukoproteinase (ALP) or with human serum albumin (hSA) (0.1, 1 or 5 μM) as a control protein for 2 hours. The inhibitory effect of pretreatment with ALP on granulocyte adherence was statistically significant at 1 and 5 μM (*p < 0.01; analysis of variance with correction for multiple testing).