Plasmacytoid dendritic cell

Plasmacytoid dendritic cells (pDCs) are innate immune cells that circulate in the blood and are found in peripheral lymphoid organs. They constitute < 0.4% of peripheral blood mononuclear cells (PBMC).[1] In humans these cells express the surface markers CD123, BDCA-2(CD303) and BDCA-4(CD304), but do not express CD11c or CD14, which distinguishes them from conventional dendritic cells or monocytes, respectively. Mouse pDC express CD11c, B220, BST-2 (mPDCA) and Siglec-H and are negative for CD11b. As components of the innate immune system, these cells express intracellular Toll-like receptors 7 and 9 which detect ssRNA and CpG DNA motifs, respectively.[2] Upon stimulation and subsequent activation, these cells produce large amounts of type I interferon (mainly IFN-α (alpha) and IFN-β (beta)), which are critical pleiotropic anti-viral compounds mediating a wide range of effects.

The number of circulating pDCs are found to be decreased during chronic HIV infection as well as HCV infection.

References

  1. ^ Tversky, J. R., Le, T. V., Bieneman, A. P., Chichester, K. L., Hamilton, R. G. and Schroeder, J. T. (2008), Human blood dendritic cells from allergic subjects have impaired capacity to produce interferon-α via toll-like receptor 9. Clinical & Experimental Allergy, 38: 781–788. doi: 10.1111/j.1365-2222.2008.02954.x
  2. ^ Gill, M.A. et al. Counterregulation between the FcεRI Pathway and Antiviral Responses in Human Plasmacytoid Dendritic Cells. The Journal of Immunology 184, 5999 -6006 (2010).