A novel technique to measure total IgM and IgG in vitro haemolysin production by mouse spleen cells, using 51Cr-labelled sheep red blood cells.

A quantitative method for measuring in vitro production of IgM and IgG haemolysis is described. Immune mouse spleen cells, 51Cr-labelled sheep red blood cells, guinea pig complement and--where applicable--rabbit anti-mouse gammaglobulin serum are incubated in the fluid phase at 37 degrees C, and the degree of chromium release measured in the supernatant. The assay gives reproducible results which compare well with the numbers of plaque-forming cells obtained in the conventional plaque-forming assay.