Pathways of Human B Lymphocyte Differentiation: A Clonal Transition between IgM and IgG Synthesis in Leukemic B Lymphocytes

Open Access
Publisher Website
Google Scholar
Abstract
Fresh human lymphoma cells from patient Gre were found to have both IgG and IgM associated with only one type of light chain (λ) on the surface membrane. After tissue culture (up to 35 days), enzymatic stripping, reagent absorptions, and ultracentrifugation, similar results were obtained. Double fluorescent labeling studies also demonstrated IgM and IgG on more than 90% of single cells. In experiments designed to study redistribution and subsequent polar capping with double labeling (rhodamine and fluorescein) techniques, we found that 1) anti-IgG or IgM and λ reagents formed mixed polar caps, 2) anti-IgG and IgM formed polar caps which suggested segregation of the two labels, and 3) prior staining with either heavy chain antiserum did not block subsequent staining with the other. We interpret these findings as suggesting the presence of a clonal switch mechanism involving IgM and IgG synthesis operating at the B lymphocyte level, presumably via an alteration in the CH gene. Additionally, when secretory Ig was looked for, we found evidence for intracellular (secretory) λ-chain synthesis without corresponding heavy chain synthesis. This latter observation further emphasizes the divergence of the secretory and membrane Ig synthetic pathways proposed by other investigators.

This publication has 0 references indexed in Scilit: