BSF-2/IL-6 does not augment Ig secretion but stimulates proliferation in myeloma cells.
Human myeloma cells were highly purified from bone marrow aspirates of 21 patients with advanced immunoglobulin G (IgG)-type multiple myeloma. B-cell stimulatory factor 2 (BSF-2)/interleukin-6 (IL-6) was originally characterized as a cytokine that can enhance immunoglobulin secretion from activated normal B cells and increase the expression of secretory-type Ig mRNA in these B cells, but that does not augment proliferation of activated B cells. However, recombinant IL-6 (rIL-6) could not enhance M-protein (IgG) secretion in freshly isolated myeloma cells in vitro but could augment proliferation of myeloma cells, although myeloma cells constitutively expressed IL-6 receptors. Furthermore, expression of secretory-type IgG (gamma-chain) mRNA in myeloma cells was not changed in the presence of IL-6. These results show that IL-6 is not an enhancing factor in Ig secretion from myeloma cells, and thus signal transduction through IL-6 in myeloma cells may be altered as opposed to activated B cells.
Tanabe
O
O
Department of Internal Medicine, Hiroshima University, Japan.
Kawano
M
M
Tanaka
H
H
Iwato
K
K
Asaoku
H
H
Ishikawa
H
H
Nobuyoshi
M
M
Hirano
T
T
Kishimoto
T
T
Kuramoto
A
A
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D015850:Interleukin-6; D007378:Interleukins / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D009101:Multiple Myeloma / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D009194:Myeloma Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000378:metabolism / Q000473:pathology
D000276:Adjuvants, Immunologic; D007136:Immunoglobulins; D015850:Interleukin-6; D007378:Interleukins; D009194:Myeloma Proteins; D011994:Recombinant Proteins