OPPOSITE EFFECT OF ALBUMIN ON THE ERYTHROCYTE AGGREGATION INDUCED BY IMMUNOGLOBULIN-G AND FIBRINOGEN

The effect of albumin on the immunoglobulin G (IgG)-induced and fibrinogen-induced aggregation of human erythrocytes was quantitatively examined by using a rheoscope combined with a television image analyzer and a computer. (i) As albumin concentration in the medium was increased, the IgG-induced erythrocyte aggregation was inhibited, while the fibrinogen-induced erythrocyte aggregation was accelerated (albumin itself was not able to aggregate erythrocytes). These relations were empirically expressed by the equations, v = aG1.8/A and v = a''F1.5 (A + b''), respectively (v, the velocity of erythrocyte aggregation; A, G and F, the concentrations of albumin, IgG and fibrinogen, respectively; a, a'' and b'', constant). (ii) The IgG-induced erythrocyte aggregation was remarkably inhibited by the addition of poly(glutamic acid), but the fibrinogen-induced erythrocyte aggregation was not. (iii) A mechanism for the interaction of immunoglobulin G and fibrinogen with the surface of erythrocytes was proposed.