Hemolysis with Human Complement, Human Cells, and Tannic Acid: Application to Complement Fixation Test

Abstract

Summary Human erythrocytes undergo lysis in the presence of tannic acid and human complement, even when cells and complement are obtained from the same blood sample. This reaction is dependent upon an optimal concentration of 0.7% sodium chloride, and an optimal concentration of between 0.06 and 0.03% tannic acid. When these substances are present in proper concentration, human complement can be titrated with reproducible results. Specific fixation of human complement by three separate antigen-antibody systems has been demonstrated, employing homologous erythrocytes sensitized by tannic acid. Antibody titers determined by this method were comparable to those obtained in the standard complement fixation test.