The murine lymphocyte receptor for IgE. IV. The mechanism of ligand-specific receptor upregulation on B cells.

• DOI: 10.4049/jimmunol.139.4.1191
• Publication Date: 2022-12-31T04:43:33Z
• Authors: W T Lee; M Rao; D H Conrad
• Keywords: 0301 basic medicine; B-Lymphocytes; Receptors, IgE; Membrane Proteins; Receptors, Fc; Immunoglobulin E; Ligands; Endocytosis; Molecular Weight; Kinetics; Mice; 03 medical and health sciences; Solubility; Animals; Receptors, Immunologic; Lysosomes

Rodent B cells respond to culture with IgE by increasing their IgE-specific Fc receptors (Fc epsilon R). The mechanism of this upregulation was characterized on R+ murine cell hybridoma lines. Measurements [35S]methionine incorporated into the R over time indicated that did not appreciably increase rate synthesis. In contrast analysis decay from surface radioiodinated demonstrated acted slow degradation. Very little endocytosis monomeric seen; this, combined observation lysomotropic agents failed inhibit degradation suggested occurs at surface. A soluble receptor immunoassay developed, using monoclonal anti-Fc R, and assay cell-bound inhibited release media immunoreactive R. Examination SDS-PAGE after isolation it 10,000 m.w. smaller than cell-associated affinity columns bind fragment, indicating ligand binding activity largely lost. Thus study IgE-dependent induction because upon surface, inhibits proteolytic cleavage surrounding medium, is inhibition causes higher levels.