The essential role of B cell stimulatory factor 2 (BSF-2/IL-6) for the terminal differentiation of B cells.
The role of recombinant B cell stimulatory factor 2 (BSF-2/IL-6) in the regulation of growth and differentiation of B cells was investigated. rBSF-2 at 200 pg/ml could induce 50% of the maximum Ig production in B lymphoblastoid cell lines, the specific activity being estimated as 5 X 10(6) U/mg. rBSF-2 augmented PWM-induced IgM, IgG, and IgA production in mononuclear cells (MNC); the effect was exerted by directly acting on PWM-induced B blast cells to induce Ig production. However, rBSF-2 did not induce any growth of activated B cells. In contrast, rBSF-2 showed a potent growth activity on a murine hybridoma clone, MH60.BSF2. The concentration required for half-maximal [3H]TdR uptake was approximately 5 pg/ml, which was 40 times less than that required for Ig induction in a B cell line. Anti-BSF-2 antibody inhibited PWM-induced Ig production in MNC, but not PWM-induced proliferation. The antibody was effective even when added on day 4 of an 8-d culture, indicating that BSF-2 is one of the essential late-acting factors in PWM-induced Ig production.
Muraguchi
A
A
Division of Immunology, Osaka University, Japan.
Hirano
T
T
Tang
B
B
Matsuda
T
T
Horii
Y
Y
Nakajima
K
K
Kishimoto
T
T
D000906:Antibodies / Q000502:physiology; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002461:Cell Line, Transformed; D006801:Humans; D006825:Hybridomas / Q000166:cytology; D007136:Immunoglobulins / Q000096:biosynthesis; D015847:Interleukin-4; D007378:Interleukins / Q000276:immunology / Q000502:physiology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology
D000906:Antibodies; D007136:Immunoglobulins; D007378:Interleukins; D011043:Pokeweed Mitogens; D011994:Recombinant Proteins; D015847:Interleukin-4