Mechanism of ligand-specific upregulation of Fc receptors for IgE on murine B cell lines

Journal Article · Wed Mar 05 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7035043

Lee, W T; Rao, M; Conrad, D H

Several studies have demonstrated that the addition of IgE to mixed lymphocyte populations will induce an increase in the number of B cell Fc receptors for IgE (Fc/sub epsilon/R). Using a Fc/sub epsilon/R/sup +/ murine B cell hybridoma, the authors have shown that IgE acts directly on the B cell to upregulate its receptor. The present studies describe the mechanism by which Fc/sub epsilon/R induction occurs. Kinetic studies of /sup 35/S-methionine labeled, affinity-purified Fc/sub epsilon/R demonstrate that IgE does not cause an increase in the rate of Fc/sub epsilon/R biosynthesis. Studies which determine the effect of IgE on the decay rates of either surface radiolabeled Fc/sub epsilon/R or Fc/sub epsilon/R on cycloheximide-treated B cells indicate that IgE causes an increase in Fc/sub epsilon/R half-life the degree of which correlates with the degree of upregulation. Thus, the effect of IgE is to slow the rate of Fc/sub epsilon/R degradation. However, the rates determined by the two methods differ, as the t1/2 determined by cycloheximide treatment for both induced and normal cells are 4-fold longer than those determined by surface labeling; this suggests the involvement of an additional protein (blocked by cycloheximide) in receptor degradation. At least in part, this degradation involves the release into the media of a approx. =35Kd soluble receptor fragment which can be specifically, isolated by a monoclonal anti-Fc/sub epsilon/R antibody. Thus, it appears that Fc/sub epsilon/R induction by ligand occurs because IgE, in binding to its receptor, inhibits proteolytic cleavage of the Fc/sub epsilon/R and its subsequent release from the cell surface.

• Research Organization: Johns Hopkins Medical School, Baltimore, MD
• OSTI ID: 7035043
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

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550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOXYLIC ACIDS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DRUGS
EVEN-ODD NUCLEI
GLOBULINS
IMMUNOGLOBULINS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LEUKOCYTES
LIGANDS
LIGHT NUCLEI
LIPOTROPIC FACTORS
LYMPHOCYTES
MAMMALS
MATERIALS
MEMBRANE PROTEINS
METHIONINE
MICE
MONOCLONAL ANTIBODIES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
VERTEBRATES