Human non-germinal center B cell interleukin (IL)-12 production is primarily regulated by T cell signals CD40 ligand, interferon gamma, and IL-10: role of B cells in the maintenance of T cell responses.
Interleukin (IL)-12 is expressed mainly in antigen-presenting cells after challenge with microbial material or after CD40 activation. Although IL-12 was cloned from human Epstein-Barr virus (EBV)-transformed B cell lines, surprisingly, CD40 ligation on murine B cells did not lead to IL-12 production, suggesting that murine B cells do not produce IL-12. Here we demonstrate that a subset of human tonsillar B cells can be induced to express and secrete bioactive IL-12. The major stimulus to produce IL-12 in human B cells was CD40 ligation. In contrast, B cell receptor cross-linking did not induce IL-12. Expression of IL-12 after CD40 activation was restricted to CD38(-)IgD+/- non-germinal center (non-GC) B cells. CD40 ligation and interferon (IFN)-gamma exhibited synergistic effects on IL-12 production, whereas IL-10 abrogated and IL-4 significantly inhibited IL-12 production by these B cells. In contrast to IL-12, production of IL-6 is conversely regulated, leading to significant increase after CD40 ligation in the presence of the T helper type 2 (Th2) cytokine IL-4. Cord blood T cells skewed towards either a Th1 or a Th2 phenotype maintained their cytokine expression pattern when restimulated with allogeneic resting B cells. Blockade of CD40 and/or IL-12 during T-B interaction significantly reduced IFN-gamma production by the T cells. This suggests a model whereby B cells produce either IL-12 or IL-6 after contact with T cells previously differentiated towards Th1 or Th2. Furthermore, IL-12 and IL-6 might provide a positive feedback during cognate T-B interactions, thereby maintaining T cells' differentiation pattern during amplification of the immune response.
Schultze
J L
JL
Department of Adult Oncology, Dana-Farber Cancer Institute, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. schultz@mbcrr.harvard.edu
Michalak
S
S
Lowne
J
J
Wong
A
A
Gilleece
M H
MH
Gribben
J G
JG
Nadler
L M
LM
D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D023201:CD40 Ligand; D003713:Dendritic Cells / Q000276:immunology; D005246:Feedback; D005434:Flow Cytometry; D006801:Humans; D007072:Immunoglobulin D / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology*; D018664:Interleukin-12 / Q000276:immunology*; D007378:Interleukins / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D014066:Palatine Tonsil / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D015703:Antigens, CD; D007072:Immunoglobulin D; D007378:Interleukins; D008562:Membrane Glycoproteins; D023201:CD40 Ligand; D018664:Interleukin-12; D007371:Interferon-gamma