title: Newly Identified TLR9 Stimulant, M6-395 Is a Potent Polyclonal Activator for Murine B Cells.
abstract: BACKGROUND
  Toll-like receptors (TLRs) have been extensively studied in recent years. However, functions of these molecules in murine B cell biology are largely unknown. A TLR4 stimulant, LPS is well known as a powerful polyclonal activator for murine B cells.
  
  
  METHODS
  In this study, we explored the effect of a murine TLR9 stimulant, M6-395 (a synthetic CpG ODNs) on B cell proliferation and Ig production.
  
  
  RESULTS
  First, M6-395 was much more potent than LPS in augmenting B cell proliferation. As for Ig expression, M6-395 facilitated the expression of both TGF-β1-induced germ line transcript α (GLTα) and IL-4-induced GLTγ1 as levels as those by LPS and Pam3CSK4 (TLR1/2 agonist) : a certain Ig GLT expression is regarded as an indicative of the corresponding isotype switching recombination. However, IgA and IgG1 secretion patterns were quite different--these Ig isotype secretions by M6-395 were much less than those by LPS and Pam3CSK4. Moreover, the increase of IgA and IgG1 production by LPS and Pam3CSK4 was virtually abrogated by M6-395. The same was true for the secretion of IgG3. We found that this unexpected phenomena provoked by M6-395 is attributed, at least in part, to its excessive mitogenic nature.
  
  
  CONCLUSIONS
  Taken together, these results suggest that M6-395 can act as a murine polyclonal activator but its strong mitogenic activity is unfavorable to Ig isotype switching.
authors.affiliation: Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Mi-Hee
authors.initials: MH
authors.lastname: Park
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Jung
authors.forename: Pyeung-Hyeun
authors.initials: PH
authors.lastname: Kim