human cytomegalovirus impairs the function of plasmacytoid dendritic cells in lymphoid organs人类巨细胞病毒损害血浆树突细胞在淋巴器官的功能.pdfVIP

Human Cytomegalovirus Impairs the Function of Plasmacytoid Dendritic Cells in Lymphoid Organs 1 1 2 Kerstin Schneider , Ursula Meyer-Koenig , Frank T. Hufert * 1 Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany, 2 Institute of Virology, University Medical Center Goettingen, Goettingen, Germany Abstract Human dendritic cells (DCs) are the main antigen presenting cells (APC) and can be divided into two main populations, myeloid and plasmacytoid DCs (pDCs), the latter being the main producers of Type I Interferon. The vast majority of pDCs can be found in lymphoid organs, where the main pool of all immune cells is located, but a minority of pDCs also circulate in peripheral blood. Human cytomegalovirus (HCMV) employs multiple mechanisms to evade the immune system. In this study, we could show that pDCs obtained from lymphoid organs (tonsils) (tpDCs) and from blood (bpDCs) are different subpopulations in humans. Interestingly, these populations react in opposite manner to HCMV-infection. TpDCs were fully permissive for HCMV. Their IFN-a production and the expression of costimulatory and adhesion molecules were altered after infection. In contrast, in bpDCs HCMV replication was abrogated and the cells were activated with increased IFN-a production and upregulation of MHC class I, costimulatory, and adhesion molecules. HCMV-infection of both, tpDCs and bpDCs, led to a decreased T cell stimulation, probably mediated through a soluble factor produced by HCMV-infected pDCs. We propose that the HCMV-mediated impairment of tpDCs is a newly discovered mechanism selectively targeting the host’s major population of pDCs residing in lymphoid organs. Citation: Schneider K, Meyer-Koenig U, Hu