Cloning and expression of the cDNA coding for a human lymphocyte IgE receptor.

The EMBO Journal (Impact Factor: 10.75). 02/1987; 6(1):109-14.
Source: PubMed

ABSTRACT Low-affinity receptors (Fc epsilon R) and secreted factors (IgE-BF) which bind to immunoglobulins of the IgE isotype play a key role in the regulation of human IgE synthesis. We report here the cloning of a cDNA coding for the Fc epsilon R of the human B-lymphoblast cell line RPMI 8866. The nucleotide sequence of this cDNA predicts a polypeptide with 321 amino acids and a mol. wt of 36,281 daltons. A functional Fc epsilon R capable of binding IgE was expressed in Chinese hamster ovary cells after stable transformation with the cDNA which had been cloned into a mammalian expression vector. Amino acid sequence analysis of IgE-BF purified from RPMI 8866 cells revealed an amino-terminal sequence of 19 residues which coincides with the predicted amino acid sequence of the Fc epsilon R, starting at residues 148 and 150. A computer search with the translated amino acid sequence of the Fc epsilon R revealed a domain of 120 amino acids having striking homology to the human asialoglycoprotein receptors.

  • Research in Immunology 05/1992; 143(4):452-456. DOI:10.1016/S0923-2494(05)80084-7
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    ABSTRACT: The soluble form of the transmembrane glycoprotein CD23 corresponding to the low-affinity receptor for the immunoglobulin E (sCD23) is found in the serum of patients with chronic lymphocytic leukemia (CLL). In this disease, an increase in sCD23 level is predictive of poor prognosis at diagnosis as well as during clinical outcome. Quantification of sCD23 is classically performed by ELISA assay, a method not routinely used in hematology laboratories. Our aim was to apply cytometric bead array (CBA) technology to measure sCD23 levels. We tested 420 serum samples, 360 from patients and 60 from healthy volunteers. We selected 3 pairs of monoclonal antibodies (moAb) recognizing the CD23 molecule that were tested in various conditions of temperature, centrifugation, washing or chemical supplementation. Satisfactory performances in terms of repeatability (CV: 5%) and reproducibility (CV: 6%) were obtained with the selected pair of antibodies, with a threshold of positivity at 6 ng/mL. CBA and ELISA techniques were correlated with a Spearman coefficient at 0.99. The reproducibility and reliability of the sCD23 CBA assay were confirmed, with a Spearman coefficient at 0.99 in a series of 23 CLL patients and 13 controls tested in 2 laboratories equipped with different cytometers and using different lots of CBA reagents. Data obtained with serum and plasma samples were correlated with a Spearman coefficient at 0.99. Our study validates a simple method that allows the clinicians to benefit from an indicator of prognosis at the diagnosis as well as a marker of the evolution of CLL disease.
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  • Research in Immunology 05/1992; 143(4):431-436. DOI:10.1016/S0923-2494(05)80078-1


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