Implanted IgE-Fc sub. epsilon. R complexes elicit IgE-mediated activation of RBL-2H3

Journal Article · Tue Jan 24 04:00:00 EST 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00428a034· OSTI ID:5517378

Ran, S; Loyter, A; Rivnay, B ^[1]

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1. Weizmann Institute of Science, Rehovot (Israel)

The high-affinity receptor for IgE (Fc{sub {epsilon}}R) is the cellular trigger of the antigen-induced activation of mast cells and basophils. To examine the functional integrity of Fc{sub {epsilon}}R, the authors have adopted a protein implantation procedure whereby the purified receptor complex was coreconstituted with Sendai virus envelopes. The latter promoted fusion of the hybrid vesicles with recipient cells such as rat basophilic leukemia, RBL-2H3, thus serving as a vehicle for the receptor. The implanted Fc{sub {epsilon}}R was complexed with {sup 125}I-labeled mouse IgE (anti-DNP) to permit receptor quantification as well as specific triggering by DNP{sub 20}BSA. Implantation in the presence of unlabeled rat IgE, which blocked the native receptors on the recipient RBL-2H3 cells, resulted in incorporation of up to 15 ng of receptor-bound IgE/10{sup 6} cells. This was roughly equivalent in amount to 10-20% of the native receptors on such cells. Various treatments that interfered with the activities of the viral envelopes reduced both receptor incorporation (3-5-fold) and cell degranulation (3-10-fold). These treatments distinguished between real incorporation of IgE-Fc{sub {epsilon}}R complexes and other mechanisms of {sup 125}I-IgE association with the recipient cells. The results indicate that the amount of IgE that was exchanged between the implanted and native receptors was minor. This conclusion was confirmed by use of an unstable variant of RBL-2H3 which expressed 10-fold less receptor on the cell surface. {sup 45}Ca uptake was also elicited by implanted receptors. They conclude that under the employed conditions the purified receptor appears to be intact with respect to the obligatory functions necessary for the exocytotic process.

• OSTI ID: 5517378
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 28:2; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ANIMAL CELLS
ANTIGENS
BASOPHILS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CALCIUM 45
CALCIUM ISOTOPES
CHEMICAL ACTIVATION
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
FUNCTIONS
GLOBULINS
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LEUKOCYTES
MAST CELLS
MATERIALS
MEMBRANE PROTEINS
MICROORGANISMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PARASITES
PROTEINS
RADIOISOTOPES
RECEPTORS
SOMATIC CELLS
UPTAKE
VIRUSES