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Potential functional role of plasmacytoid dendritic cells in cancer immunity
Author(s) -
Kim Ryungsa,
Emi Manabu,
Tanabe Kazuaki,
Arihiro Koji
Publication year - 2007
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/j.1365-2567.2007.02579.x
Subject(s) - tlr9 , immunology , immune system , biology , antigen , plasmacytoid dendritic cell , myeloid , dendritic cell , antigen presenting cell , priming (agriculture) , cancer research , t cell , biochemistry , gene expression , botany , germination , gene , dna methylation
Summary Plasmacytoid dendritic cells (pDCs), as well as myeloid dendritic cells (mDCs), have a dual role not only in initiating immune responses but also in inducing tolerance to exogenous and endogenous antigens. Tumour antigens originate from endogenous self‐antigens, which are poorly immunogenic and also subject to change during tumour progression. In general, tumour antigens derived from apoptotic cells are captured by immature mDCs, antigen presentation by which is most likely to result in immune tolerance. In contrast, tumour antigens may be taken up by pDCs through Toll‐like receptor 9 (TLR9) via receptor‐mediated endocytosis. TLR9‐dependent activation of pDCs results in the secretion of pro‐inflammatory cytokines such as interleukin (IL)‐12 and type I interferons (IFNs) through a MyD88‐dependent pathway. Type I IFNs also activate mDCs for T‐cell priming. Although pDCs recruited to the tumour site are implicated in facilitating tumour growth via immune suppression, they can be released from the tumour as a result of cell death caused by primary systemic chemotherapy, and can then be activated through TLR9. Thus, synergistically with mDCs, pDCs may also play a crucial role in mediating cancer immunity. In this review, the potential functional duality and plasticity of pDCs mediated by TLR9 ligation in cancer immunity will be discussed.