ADHESION OF HUMAN RED-BLOOD-CELLS AND SURFACE-CHARGE OF THE MEMBRANE

To elucidate the mechanism by which red blood cells (RBC) participate in thrombus formation, we investigated the mechanism of adhesion betwe en human RBC. Our study showed that the morphology of RBC was changed by various cationic reagents, inducing adhesion between RBC. When RBC suspended in PBS buffer containing sodium phosphate (PBS(Na)) or potas sium phosphate (PBS(K)) were treated with cationic reagents, stronger adhesion occurred between RBC treated with the latter. When concentrat ions of the reagents were low, adhesion was released and the RBC resum ed its original morphology after washing. However, when the concentrat ions of reagents were high, the morphology did not normalize, although the adhesion was released. When fresh RBC were treated with cationize d ferritin (CF), CF bound to the periphery of RBC membranes and induce d adhesion. However, when RBC were induced to adhere strongly by a cat ionic reagent, no binding of CF to the membrane was not observed. When RBC were treated with CF, bindings between substances outside the mem branes and bindings between the membranes and substances outside the m embranes were observed. When RBC treated with neuraminidase to remove 85-90% of sialic acid were treated with the cationic reagents, both ad hesion between RBC and morphological change were reduced. When RBC wer e pretreated with polyclonal antibody against human RBC membrane band 3 protein, treatment with the cationic reagents did not induce adhesio n and morphological change of RBC. Further, when RBC induced to adhere by the cationic reagents were treated with the polyclonal antibody ag ainst band 3, in the case of weak adhesion, the adhesion was released and the RBC resumed its original morphology. However, in the case of s trong adhesion, the morphology did not return to normal although the a dhesion was released. These results suggest that the adhesion between RBC induced by cationic reagents was due to changes in the charge on t he membrane surface, involving polysaccharide chains and membrane surf ace proteins.