Reactivity of Polymer (19S) and Monomer (7S) Forms of γM with Anti-γM Serum

[摘要] An anti-γM serum which distinguishes between 19SγM and a low-molecularweight γM from human serum (γMs-N) was prepared by immunizing a goat with normal human γM in Freund's complete adjuvant; it was absorbed with γG and hypogammaglobulinemic serum and was specific for γM. The reactivity of this antiserum was examined with 19SγM, with the γM monomer produced by reduction and alkylation (γMs-RA), and with the γM monomer prepared by reduction alone (γMs-R). In agar double diffusion the 19SγM band spurred over the bands formed by γMs-RA and γMs-R whereas the bands formed by γM monomers fused. Mixtures of 19SγM and γMs-RA formed concentric zones of precipitation in radial immunodiffusion and produced two bands in agar double diffusion. By quantitative precipitin analysis, with 19SγM the antiserum contained 30 µg Ab N/0.1 ml serum and with γMs-RA, 19 µg Ab N/0.1 ml. After absorption at equivalence with γMs-RA the antiserum still precipitated with 19SγM and Fc-γM but did not precipitate with Fab-γM. The precipitin reaction between 19SγM and the anti-γM serum absorbed with γMs-RA was inhibited by three γM subunits (γMs-RA, γMs-R, and γMs-N). Thus, the antiserum is reactive with an antigenic determinant on the Fc portion of the µ chain present on both 19SγM and the γM subunits. The difference in the reactivity of the antiserum with 19SγM and the γM subunits may be related to the number of specific antigenic determinants on these molecules.

[学科分类] 生物科学（综合）