The electrophoretic properties of red blood cells after reaction with influenza virus hemagglutinin

Abstract 1. 1. The mobilities of guinea pig red blood cells subjected to the action of PR8 influenza type A virus hemagglutinin have been measured at several values of pH and ionic strength ( pH 7.9−5.7, Γ 2 0.172−0.0043 ). 2. 2. The negative surface charge density of “treated” cells is usually less than that of control cells under similar conditions; at pH 7 and physiological ionic strength the difference amounts to about 1000 e.s.u. or 2 × 10 12 electrons/sq. cm. 3. 3. The reciprocal surface charge density of treated cells varies linearly with reciprocal ionic strength; the slope K is almost the same as for control cells. 4. 4. The charge density of treated cells becomes sensitive to pH at low ionic strengths; the resulting curves are quite similar to those of control cells under the same conditions, but with a constant displacement in the direction of a smaller net negative charge density. 5. 5. The changes associated with receptor decomposition are attributed to the formation of free cationic groups comparable to those formed by the action of RDE upon Tamm and Horsfall's urinary inhibitor. 6. 6. It is suggested on the basis of rough calculations that the red blood cell receptor for influenza A virus consists of a single molecule comparable to the urinary inhibitor. 7. 7. Since the supplementary positive charge on the red blood cell produced by virus action varies with ionic strength in the same manner as the net negative charge of the untreated cell, it is assumed to be attached to the same labile elements of the cell membrane and to participate in the same structural rearrangement brought about by decreased ionic strength.