Use of 2-Mercaptoethanol for Distinguishing Between IgM and IgG Antibody-Producing Cells of Mice Immunized with Bovine γ Globulin

Abstract

Spleen cells from mice immunized with heat-aggregated bovine γ globulin (BGG) were assayed by the technique of localized hemolysis in gel. Target cells were prepared by the conjugation of BGG to sheep red blood cells by means of chromic chloride. No anti-BGG direct plaques were developed by the addition of guinea pig serum alone throughout the period under examination. Practically all of the plaques were obtained by the indirect method with the aid of anti-mouse immunoglobulin antiserum, and at least two categories of cells which secrete either 2-mercaptoethanol (2ME)-sensitive or 2ME-resistant antibodies were involved. The pretreatment of gel plates with 2ME after cellular antibodies have diffused out may be recommended for distinguishing between IgM and IgG antibody producers against protein antigens. We also discuss why direct plaques do not appear in this experiment.