Isolation and partial characterization of Fc gamma-binding proteins of human leukocytes.

Abstract

A B S T R A C T We isolated and partially characterized three Fe-binding macromolecules from human leukocytes. Mononuclear cells from normal individuals and from five patients with chronic lymphocytic leukemia and neutrophils from normal donors were surface radiolabeled by using 125I and lactoperoxidase.After detergent solubilization of the cells, Fc,-binding macromolecules were purified by repetitive affinity chromatography under a variety of conditions and analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis.Three radiolabeled macromolecules were isolated that retained specific ability to bind to Fc fragments.A 52,000-64,000-mol wt macromolecule was isolated from normal mononuclear and polymorphonuclear cells. A 43,000-mol wt band was characteristic of mononuclear cells, particularly from patients with chronic lymphocytic leukemia. A 33,000-mol wt molecule could be obtained from normal leukocytes under conditions that suggest it might be a proteolytic fragment.

Identification of a third component of complement-binding glycoprotein of human platelets.

“…The mean Mr ofthe "upper" and "lower" bands is 64,000 and 53,000, respectively. Molecules with M, of42,000 and 53,000 are prominent in the IgG lane; this Mr is in the range expected for the Fcy receptor (39)(40)(41). Two prominent bands with an Mr of 132,000 and 90,000 bound to all three columns.…”

A Comparison between Fc Receptors for IgGl and IgG3 on Human Monocytes and Lymphocytes Using Anti-Rh Antibodies

“…The observation of Gil bert et al [10] that stimulated lymphocytes can disclose Fc receptors which bind other subclasses than IgG3 might support the sup position that one receptor binds both sub classes and that its specificity depends on the physiological status of the cell. The possibil ity that several different receptors exist might be suggested from the observations of other authors [13,14,19], who in isolated Fc receptors, discovered two or three molecules differing in molecular weight.…”

Ontogeny of Fc receptors and complement receptor (CR3) during human myeloid differentiation.

“…There are several reports of purification of human Fc receptors in the general range of 40,000-70,000 Mr (40)(41)(42) by affinity chromatography on columns of immobilized IgG. We have explored the heterogeneity of human Fc receptors using affinity chromatography on IgGl-Sepharose, immunoprecipitation with monoclonal anti-Fc.,Rl antibody 3G8, and immunoprecipitation with a rabbit serum elicited by 3G8-affinity purified FcR1O.…”