Simultaneous core 2 beta1-->6N-acetylglucosaminyltransferase up-regulation and sialyl-Le(X) expression during activation of human tonsillar B lymphocytes. 
We have investigated the regulation mechanism of the surface sialyl-Le(X) (sLe(X)) expression level in tonsillar B cells during activation.  sLe(X) antigen became strongly positive after activation, while resting B cells were weakly positive.  sLe(X) structures were mainly located on O-linked oligosaccharide chains of glycoprotein.  Transcripts of FucT-VII and core 2 GlcNAc transferase (C2GnT) were up-regulated after activation, while those of ST3GalIV and beta1-->4GalT-I were expressed constitutively.  However, the up-regulation of C2GnT was more dramatic than that of FucT-VII.  These results suggest that sLe(X) expression level is regulated by C2GnT during tonsillar B cell activation.