Abstract: Nucleotide sequences encoding a protein with Fc receptor activity or a fragment thereof that is capable of binding the Fc region of immunoglobulin and polypeptides with Fc receptor activity are provided. Proteins which exhibit enhanced or reduced immunoglobulin binding ability relative to native Fc receptors and nucleotides encoding these proteins also are provided. The invention also provides methods of determining the presence of immunoglobulin, detecting an immune complex, removing immunoglobulin from a body fluid and treating disease using the proteins.

Abstract: A receptor for the Fc portion of immunoglobulin, derived from mouse or human cells, the receptor exhibiting the ability to bind to the Fc portion of mouse and human immunoglobulin and comprising a transmembrane proteins having about 280-301 amino acids including two substantially regularly spaced pairs of Cys residues and two or four potential N-linked glycosylation sites. The present invention also provides for a nucleotide sequence, gene, cDNA clone or a vector containing same capable of encoding the above receptor.