Journal of Microbiology and Biotechnology, 2013, 01, 1159─1166

Orientia tsutsugamushi infection induces CD4+ T cell activation via human dendritic cell activity

Hyuk Chu, SungMoo Park, In Su Cheon, MiYeoun Park, ByoungShik Shim, ByoungCheol Gil, Woon Hee Jeung, KyuJam Hwang, KiDuk Song, KeeJong Hong, Manki Song, HangJin Jeong, Seung Hyun Han, CheolHeui Yun

Abstract

Orientia tsutsugamushi, a gram-negative bacterium, causes severe acute febrile illness in humans. Despite this danger, the route of infection, infectivity, and protective mechanisms of the host’s immune response to O. tsutsugamushi are unclear. Dendritic cells (DCs) are one of the most important cell types in bridging the innate and adaptive immune responses. In this study, we observed that O. tsutsugamushi infects and replicates in monocyte-derived DCs (MODCs). During infection and replication, the expressions of the cytokines IL-12 and TNF-α, as well as the co-stimulatory molecules CD80, CD83, CD86, and CD40, were increased in MODCs. When O. tsutsugamushi-treated MODCs were co-cultured with autologous CD4+ T cells, they enhanced production of IFN-γ, a major Th1 cytokine. Collectively, our results show that O. tsutsugamushi can replicate in MODCs and can simultaneously induce MODC maturation and increase proinflammatory cytokine levels in MODCs that subsequently activate CD4+ T cells.

• ISBN or ISSN: 1017-7825

• 본 연구는 질병관리본부 연구개발과제(과제번호 2010-N52001-00) 연구비를 지원받아 수행되었습니다.
• This research was supported by a fund(code 2010-N52001-00) by Research of Korea Centers for Disease Control and Prevention.