Susceptibility to ApxIIIA-induced cell death closely depends on the rate of LFA-1 ectopic expression in human erythroleukemic K-562 cells provided the contributing CD18 subunit is that of the pig. Values (squares, circles, triangles and lozenges) are means ± SD from three representative experiments in which mean LFA-1 expression rate (horizontal SD) and mean PI incorporation (vertical SD) were measured by flow cytometry. LFA-1 cell-surface expression rate typical of each experiment was defined as the mean proportion of Alexa 488-positive cells calculated from two independent labelling procedures, one using MCA1972 (anti-CD18) and the other MCA2308 or 555382 (anti-CD11a) as primary antibody.