Quantitative studies of Gm allotypes—III: Some effects of IgG aggregation in radioimmunoassays using human IgM and rabbit IgG anti-Gm antibodies☆

Abstract Two radioimmunoassays for Gm allotypes using human IgM (SNagg) and rabbit IgG anti-Gm antibodies are described. All the antisera tested reacted much better with the corresponding Gm antigen present on aggregated IgG than with the same allotype on 7S IgG. Consequently, aggregated Gm(+) IgGs are used as iodinated tracers in these RIAs, while 7S IgGs are used as standards for quantitative studies. Serum concentrations ofGlm(1).Glm(3) and G3m(11) were measured in populations of homozygous and heterozygous normal Caucasian donors. These values agreed with previous results obtained with other methods.