Fluid shear modulates the molecular interactions between polymorphonuclear leukocytes and colon carcinomas

This study compares the kinetics, adhesion efficiency, and molecular requirements of polymorphonuclear leukocyte (PMN) binding to two colon adenocarcinoma cell-lines, the ICAM-1-negative/sLe^x-bearing LS174T and the ICAM-1-expressing/sLe^x-low HCT-8 as a function of hydrodynamic shear rate (50-1600 sec^-1). The efficiency of both PMN homotypic and PMN-colon carcinoma heterotypic interactions, defined as the fraction of collisions between respective cells that result in aggregation, decreases sharply at low shear. At higher shear, PMN homotypic efficiency remains relatively unchanged, while heterotypic efficiencies continue to decrease with PMN binding to LS174T cells being more efficient than to HCT-8 cells. The relative contributions of LFA-1 and Mac-1 as well as their respective ligands on HCT-8 cells to heterotypic aggregation were investigated in the presence of fluid shear.