Quantitation of partially purified H-2 antigens by micro-complement fixation.

The micro-complement fixation test has been evaluated as an assay method for monitoring the purification of H-2 antigens. Antigens were extracted from spleen and tumor cell membranes with 3 M potassium chloride. The extracted antigens were measured in micro-complement fixation tests with polyspecific and monospecific anti-H-2 alloantisera at two steps in the purification process. In the initial steps of purification, partial complement fixation curves were obtained with H-2 antigens from spleen cells of three strains of mice and a complete curve with antigens from tumor cells. Antigens from spleen and tumor cells were measured also following separation on Sephadex G-200 and G-75. The data indicate that micro-complement fixation can be used as a direct, sensitive assay system for the purification of major histocompatibility antigens.