Idiotypic Determinants on the Monoclonal Immunoglobulins Associated with Papular Mucinosis

[摘要] Quantitative idiotypic studies were performed with monoclonal proteins from nine patients with the rare dermatologic disease papular mucinosis (PM). The PM serum protein is a basic “cathodal” IgG-1 monoclonal protein of λ light chain type and we postulated that these proteins might represent antibodies against acidic mucopolysaccharide components in the skin deposits or subcutaneous tissue of the PM patients. Specific anti-idiotypic antisera were prepared against each of four isolated PM proteins. The inhibition of the reaction between the 125I-labeled F(ab′)2 fragment of a PM protein and its homologous anti-idiotypic antiserum was tested with a series of proteins. In each case the homologous PM protein produced 98 to 100% inhibition whereas no inhibition was obtained with the other eight PM proteins, by a panel of 10 myeloma proteins of different classes, subclasses and light chain types, nor by fractions of normal IgG from PM patients or normal subjects. No inhibition was produced by a 2000-fold excess of normal IgG, suggesting that the idiotypic determinants of PM proteins are not represented in significant numbers of molecules in normal IgG. Further experiments for cross-reactivity between the four anti-idiotypic antisera found only slight cross-reactivity with one antiserum. Antisera against the γ chains of normal IgG from each of the four PM patients and from normal subjects consistently reacted with a small but significant percentage of the F(ab′)2 fragments of the PM proteins; the specificity was apparently not due to anti-light chain activity nor anti-human Fc activity and may have been directed against determinants in the variable region of the Fd portion.There was no evidence for significant sharing of common idiotypic determinants by the PM proteins suggesting that, if these proteins were antibodies against acidic skin compounds, their specificities were directed against different compounds or against different determinants on the one compound.

[学科分类] 生物科学（综合）