A soluble form of the human Fc receptor FcγRIIA: Cloning, transcript analysis and detection

E. F. Rappaport*, D. L. Cassel, D. O. Walterhouse, S. E. McKenzie, S. Surrey, M. A. Keller, A. D. Schreiber, E. Schwartz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The Fcγ receptors (FcγR) are glycoproteins that bind the Fc region of immunoglobulin G. Human hematopoietic cells express three biochemically distinct classes of Fcγ receptors: FcγRI (CD64), FcγRII (CD32) and FcγRIII (CD16). Complementary DNA (cDNA) clones for each of the human Fcγ receptors have been isolated from myeloid and lymphoid cells. We describe the isolation and characterization of four FcγRII clones from a cDNA library obtained from a megakaryocyte-like cell line, human erythroleukemia (HEL). Three clones encode the FcγRIIA transmembrane (TM) form, while one novel clone lacks the TM region but retains the cytoplasmic domain. By conducting reverse transcription coupled to polymerase chain reaction (PCR), we found transcripts coding for this unique form of receptor in RNA from platelets, HEL cells and a second megakaryocyte-like cell line, CHRF-288-11. These results were confirmed by RNase protection analysis of RNA from HEL cells. The structure of the novel cDNA suggested that it codes for a soluble form of FcγRIIA. A soluble FcγRlI protein was detected in the conditioned medium from HEL cells but not from the FcγRII-negative T cell line, Jurkat, by immunoprecipitation with the anti-FcγRII monoclonal antibody (mAb), IV.3. The immunoprecipitated protein was of the expected size for a soluble FcγII lacking the TM region but retaining the cytoplasmic domain. Soluble FcγRIIA may be important in modulating the interaction between immune complexes and membrane-associated FcγRII.

Original languageEnglish (US)
Pages (from-to)689-696
Number of pages8
JournalExperimental Hematology
Volume21
Issue number5
StatePublished - 1993

Keywords

  • Alternative splicing
  • Fc receptors
  • Platelets
  • Soluble receptors

ASJC Scopus subject areas

  • Molecular Biology
  • Hematology
  • Genetics
  • Cell Biology
  • Cancer Research

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