Characterization of the high-affinity cell-surface receptor for murine B-cell-stimulating factor 1.

Abstract

Radiolabeled recombinant murine B-cellstimulatory factor 1 (BSF-1) was used to characterize receptors specific for this lymphokine on the surface of primary B and T cells and in vitro cell lines representing the B-cell, T-cell, mast cell, macrophage, and myelomonocytic lineages. BSF-1 binding was rapid and saturable at 40C and 370C with a slow dissociation rate. On all cell types examined, BSF-1 bound to a single class of high-affinity receptor (<2000 receptors per cell) with a Ka of 101o-101I M-'. Receptor expression on resting primary B and T cells was low (<100 receptors per cell), whereas activation with lipopolysaccharide or Con A produced a 5-to 10-fold increase in receptor numbers. Among a panel of lymphokines and growth hormones, only unlabeled BSF-1 was able to compete for the binding of 1HI-labeled BSF-1. Affinity crosslinking experiments resulted in the identification on all cells tested of a receptor protein with an average Mr of 75,000.

Immunocytochemical demonstration of the binding and internalization of growth hormone, B-cell stimulating factor-1 and thy-1.2 in murine lymphocytes.

“…The mechanism of a second messenger model by which interleukins regulate gene expression and T-cell proliferation has been described by Farrar et al (6). However, the demonstration of the BSF-I/IL-4 receptor on the lymphocytes (16,21) and the accumulated BSF-1/IL-4 ligands in the lymphocytes (27) were parrallel to our immunocytochemical observations that BSF-1/IL-4 bound and then internalized in the splenic lymphocytes.…”

“…Recently, attention has been focused on the internalization and accumulation of specific antigens and/or receptors located on B-cell or T-cell surfaces (26,27). The growing number of polypeptide modulators involved in the immune system (20) and various receptors on lymphocytes has also been demonstrated (8,10,15,16,21,29). The present immunocytochemical method provides an indirect visual probe to the evidence that GH and growth factor, or marker antigens located on the cell surface of lymphocytes can induce ligand-mediated internalization of antigen-ligand-complexes.…”

“…It stimulates the proliferation of B cells (5) as well as T cells (10). The receptors for BSF-1/IL-4 have been detected on IL-2, IL-3 dependent cell lines and B cells, T cells, macrophages and myelomonocytes at different levels (21). The expression of the BSF-1/IL-4 receptors on B cells or T cells indicates the diverse activities stimulated by BSF-1/IL-4.…”

“…Different methods have been used to detect the binding hormones and regulation of their specific receptors on the surface of lymphocytes in vitro (4,5,10,(12)(13)(14)(15)(16)(17)(18)21). The presence of radioactive-labelled human growth hormone (GH) and its receptor on a human lymphocyte cell line, IM-9, has been demonstrated, and in addition, the concentration of GH-receptors is controlled by the binding of GH to the cell surface (13).…”

Splenectomy and Salmonella Typhi Exposure Lead to Quantitative Alterations of Bone Marrow B220+ Cells and CD4+ T Cells on BALB/c Mice

“…However, the normally expected high rate of B cell lymphopoiesis in the bone marrow did not occur due to the splenectomy. To achieve homeostasis, a high migration rate should be followed by an increase in the rate of lymphopoiesis, as indicated by the higher number of lymphocytes in both the peripheral organs and central organs, for example the bone marrow and thymus, [32,35,36] but there was no homeostatic anomaly in our study. Foster and Trejdosiewicz [37] explained why this might happen by showing that a splenectomy does not affect the proliferation of B cells in the bone marrow and lymph nodes.…”