Quantitative studies of hemagglutination. Use of an electronic particle counter to investigate factors influencing cell aggregation.

Abstract

Summary. A series of factors influencing antibody‐mediated red cell agglutination has been investigated quantitatively, employing an electronic cell counting technic. Increasing duration of red cell storage was shown to decrease mean red cell number per agglutinate more significantly than it did total percentage agglutination. The expected enhancement by lowered temperatures of agglutination in a saline‐agglutinating system was demonstrated. Hydrogen ion concentration had little effect on agglutination in the pH ranges 6.2 to 8.3 in either a saline agglutinating system or one employing antiglobulin serum. Hypotonic suspending media resulted in enhanced agglutination in both types of systems. In a saline agglutinating system increased phosphate concentrations enhanced agglutination, while isotonic solutions of NaCl, KCl or MgCl2 yielded results comparable to those obtained employing triethanolamine‐buffered saline. Increased agglutination in both systems was produced by increasing the duration or speed of centrifugation, while more violent agitation during the disaggregation phase of the experiments yielded less fully agglutinated systems after equilibrium was attained.