Characterization of Mouse B Lymphoma Cells (CH12F3-2A) for the Study of IgA Isotype Switching

IgA Isotype Switching 연구를 위한 마우스 B Lymphoma Cell (CH12F3-2A)의 특성 연구

  • Jang, Young-Saeng (Department of Microbiology, College of Natural Sciences, Kangwon National University) ;
  • Choi, Seo-Hyeun (Department of Microbiology, College of Natural Sciences, Kangwon National University) ;
  • Park, Seok-Rae (Department of Microbiology, College of Natural Sciences, Kangwon National University) ;
  • Kim, Hyun-A (Department of Microbiology, College of Natural Sciences, Kangwon National University) ;
  • Park, Jae-Bong (Department of Biochemistry, College of Medicine, Hallym University) ;
  • Kim, Pyeung-Hyeun (Department of Microbiology, College of Natural Sciences, Kangwon National University)
  • 장영생 (강원대학교 자연대학 미생물학과) ;
  • 최서현 (강원대학교 자연대학 미생물학과) ;
  • 박석래 (강원대학교 자연대학 미생물학과) ;
  • 김현아 (강원대학교 자연대학 미생물학과) ;
  • 박재봉 (한림대학교 의과대학 생화학교실) ;
  • 김평현 (강원대학교 자연대학 미생물학과)
  • Published : 2004.12.30

Abstract

Background: It is well known that IgA isotype switching is induced by $TGF-{\beta}1$. LPS-activated mouse normal B cells well differentiate into IgA secreting plasma cells under the influence of $TGF-{\beta}1$. Nevertheless, there are lots of difficulties in studying normal B cells in detail because it is not simple to obtain highly purified B cells, showing low reproducibility and transfection efficacy, moreover impossible to keep continuous culture. To overcome these obstacles, it is desperately needed to develop B cell line which acts like normal B cells. In the present study, we investigated whether CH12F3-2A lymphoma cells are appropriate for studying IgA isotype switching event. Methods: CH12F3-2A B cell line was treated with LPS and $TGF-{\beta}1$, then levels of germ-line (GL) transcripts were measured by RT-PCR, and $GL{\alpha}$ promoter activity was measured by luciferase assay. In addition, membrane IgA (mIgA) expression and IgA secretion were determined by FACS and ELISA, respectively. Results: $TGF-{\beta}1$, regardless of the presence of LPS, increased level of $GL{\alpha}$ transcripts but not $GL{\gamma}2b$ transcripts. However, IgA secretion was increased dramatically by co-stimulation of LPS and $TGF-{\beta}1$. Both mIgA and IgA secretion in the presence of $TGF-{\beta}1$ were further increased by over-expression of Smad3/4. Finally, $GL{\alpha}$ promoter activity was increased by $TGF-{\beta}1$. Conclusion: CH12F3-2A cell line acts quite similarly to the normal B cells which have been previously reported regarding IgA expression. Thus, CH12F3-2A lymphoma cell line appears to be adequate for the investigation of the mechanism(s) of IgA isotype switching at the cellular and molecular levels.

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