Augmentation of hemolytic efficiency of anti-hapten IgG antibody by anti-IgG antibody is primarily the function of the anti-hapten IgG

IgG anti-cell antibodies are inefficient in inducing cell lysis by complement. C mediated lysis by anti-cell IgG can be augmented by the use of C fixing anti-antibody. We have studied augmentation of rabbit anti-Forssman IgG, rabbit anti-methotrexate IgG and rabbit anti-folinic acid IgG antibodies by rabbit anti-allotype IgG antibodies. Large variability (from a low of 2 to a high of over 100) was found in augmentation efficiency even with the same anti-allotype antibody; the variability was primarily the function of the anti-hapten antibody. It was concluded that quantitative studies on anti-hapten IgG production relying on augmented hemolysis may lead to misleading conclusions.