Temperature Gradient Dissociation of Red Cell Antigen–Antibody Complexes in the Polybrene Technique*

Abstract

S ummary . The automated Polybrene technique for the detection of red cell antibodies has been adapted for the study of the thermal properties of various red cell antigen‐antibody reactions. A continuous flow of antibody‐induced red cell aggregates was subjected to gradually increasing temperature. The results produced ‘temperature gradient dissociation curves’ (TGDC) which represented not the influence of temperature on antibody uptake but the dissociation of already established immunological bonds. Temperature of dissociation was influenced by the thermal properties of the antibodies and by their concentration. Antibodies could be classified into ‘cold’, ‘intermediate’ and ‘warm’ reacting groups. The technique was also applicable to the study of antibodies that occur on sensitized red cells and, particularly, to patients with acquired haemolytic anaemia. Determination of TGDC has provided a new approach to the study of autoimmune diseases, and may have significant clinical implications.