Plasmacytoid Dendritic Cells Induce Plasma Cell Differentiation through Type I Interferon and Interleukin 6

Speaker: 黃文彥

Commentator: 余俊強  老師

Date: 2003/10/1, 15:00~16:00

Place: Room 601

Abstract:

Dendritic cells (DCs) play a central role in initiating and linking innate and adaptive immune responses to pathogens.¹  There are two main DCs subsets: the CD11c⁺ myeloid DCs and CD11c^-/CD123⁺ /CD4⁺ plasmacytoid dendritic cells (pDCs).²  pDCs are known to produce IFN-a/b upon exposure to viruses.³  In this paper, the authors depleted pDCs from PBMC with BDCA4-coupled beads⁴ and showed abrogation of IgG production.  Moreover, purified pDCs triggered CD40-activated B cells differentiation into CD38^hi plasma cells and enhanced the production of influenza-specific antibodies by these B cells co-cultured with viruses.  The activation of B cells by pDCs is contact independent and through IFN-a/b and IL-6.  Using antibodies to neutralization either IFN-a/b or IL-6 abolished the pDC-induced IgG secretion by B cells, and IFN-a/b but not IL-6 induced phenotypic differentiation of activated B cell into CD38^hi plasma cells.  Thus, CD40-activated B cells differentiate into non-Ig-secreted CD38^hi plasmablasts then into Ig-secreted plasma cells by IFN-a/b and IL-6, respectively.  In conclusion, pDCs play a role to cause B cell differentiation and antibody production.⁵

Reference:

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2.     Liu Y.J. (2001) Dendritic cell subsets and lineages, and their functions in innate and adaptive immunity. Cell 106:259-262.

3.     Asselin-Paturel, et. al (2001). Mouse type I IFN-producing cells are immature APCs with plasmacytoid morphology. Nat. Immunol. 2:1144–1150.

4.     Dzionek, A., et al. (2000). BDCA-2, BDCA-3, and BDCA-4: three markers for distinct subsets of dendritic cells in human peripheral blood J. Immunol. 165:6037–6046.

5.     Jego, G, et. al. (2003). Plasmacytoid dendritic cells induce plasma cell differentiation through type I interferon and interleukin 6. Immunity 19:225-234