Platelet aggregation as a quantitative immunologic technique.

Abstract

A rapid quantitative immunologic method based on the sensitivity of platelets to immune complexes is described. Platelet-rich-plasma (PRP) from sensitized animals exposed to various concentrations of antigen (or antigen t anti-serum) is sedimented. The number of aggregated platelets is obtained from the difference between the number of initial platelets and the non-sedimenting platelets. The total number of sedimenting platelets thus obtained is a function of the antigen or antibody levels. The platelet aggregation technique is effective with antigens such as bovine serum albumin (BSA), bovine gamma globulin (BGG), human influenza virus (HIV), and tuberculin purified protein derivative (PPD). The effects of reaction time, temperature, chelation, and platelet dilution were studied. The method is as sensitive as the passive hemagglutination and complement fixation methods.