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

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.

• Authors: Hyuk Chu, Sung-Moo Park, In Su Cheon, Mi-Yeoun Park, Byoung-Shik Shim, Byoung-Cheol Gil, Woon Hee Jeung, Kyu-Jam Hwang, Ki-Duk Song, Kee-Jong Hong, Manki Song, Hang-Jin Jeong, Seung Hyun Han, Cheol-Heui Yun
• Journal: Journal of microbiology and biotechnology (J Microbiol Biotechnol) Vol. 23 Issue 8 Pg. 1159-66 (Aug 2013) ISSN: 1738-8872 [Electronic] Korea (South)
• PMID: 23727805 (Publication Type: Journal Article, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, CD
• Cytokines

Topics

• Antigens, CD (biosynthesis, genetics)
• CD4-Positive T-Lymphocytes (immunology)
• Cells, Cultured
• Coculture Techniques
• Cytokines (biosynthesis, genetics)
• Dendritic Cells (immunology, microbiology)
• Gene Expression Profiling
• Humans
• Orientia tsutsugamushi (immunology)
• Scrub Typhus (immunology, microbiology)