Augmentation of signal transducer and activation of transcription (STAT)6 and STAT3 expression in stimulated B and T cells

Signal transducer and activation of transcription (STAT)6 has a central rol e in the signal transduction of interleukin (IL)-4 and IL-13. It has recent ly been revealed that STAT3 is also involved. STAT6 and STAT3 are expressed ubiquitously; however, it remains unknown how STAT6 and STAT3 expression i s regulated. In this study, we found that STAT6 expression was augmented at the transcription level in B and T cells stimulated with anti-IgM antibody and anti-CD40 antibody or PMA and ionomycin, respectively, and that STAT3 expression was similarly augmented in the stimulated B cells. The stimulate d B and T cells showed enhancement of STAT6 activation and CD23 expression induced by IL-4 and IL-13. Augmentation of STAT6 and STAT3 would be a mecha nism of the amplification of the IL-4 and IL-13 signals in stimulated B and T cells. (C) 2000 Academic Press.