|
||
J. Exp. Med.,
Volume 189, Number 1, January 4, 1999 1-12
, and IL-10: Role of B Cells in the
Maintenance of T Cell Responses
By
From the Department of Adult Oncology, Dana-Farber Cancer Institute, Department of Medicine,
Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
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)-
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-
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.
;
interleukin 10
This article has been cited by other articles:
| TABLE OF CONTENTS |
|