Comparative Studies on Monotypic IgMλ and IgGκ from an Individual Patient

A comparative idiotypic antigenic analysis of an IgMλ and an IgGκ paraprotein obtained from sera of an individual patient, Br, revealed the presence of very similar idiotypic determinants associated with the VH regions of the Br µ- and γ-chains. In addition, the IgGκ protein expressed light (L) chain-associated idiotypic determinants which were not evident on the IgMλ protein or its isolated L chains. Extensive tests of specificity revealed that the shared VH idiotypic determinants were not present in large weight amounts of heterologous nonspecific IgM and IgG, nor on Ig molecules contained in a large number of normal and myeloma sera.