TNF-alpha suppresses dendritic cell death and the production of reactive oxygen intermediates induced by plasma withdrawal.
Mature dendritic cells (DCs) were generated by culturing human peripheral blood monocytes for 7 days and, then, treating them with a cytokine cocktail for 2 days. The viability of the mature DCs (Day 9) obtained was approximately 60-70%, and this gradually declined when they were recultured in X-VIVO 15 media containing 2% human plasma (40% viability after 3 days of reculture). DC death accelerated on withdrawing plasma from the culture (20% viability after 3 days). However, the addition of tumor necrosis factor-alpha (TNF-alpha) to the medium completely restored DC viability in the absence of plasma. Such a protective effect was not afforded by other cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1alpha (IL-1alpha), IL-4, IL-6 and prostaglandin E2 which are used for the maturation of DCs. These results indicate that TNF-alpha is specifically required to maintain the viability of mature DCs. The withdrawal of plasma rapidly (within 15 min) elevated cellular levels of reactive oxygen intermediates (ROIs), which have been proposed to regulate the ability of DCs to control inflammatory reactions. The possibility that ROIs act as mediators of DC death was eliminated by the observation that scavengers of ROIs, such as catalase, N-acetylcysteine, glutathione, failed to prolong DC life span in the absence of plasma. Interestingly, TNF-alpha was found to almost completely abolish the production of ROIs induced by plasma withdrawal. To summarize, our results suggest that TNF-alpha controls not only the inflammatory functions of DCs but also their survival.
Um
Hong-Duck
HD
Laboratory of Experimental Pathology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Cho
Young-Hun
YH
Kim
Do Kyun
DK
Shin
Jong-Ran
JR
Lee
Yung-Jae
YJ
Choi
Kwang-Sung
KS
Kang
Jin-Moon
JM
Lee
Min-Geol
MG
D000111:Acetylcysteine / Q000494:pharmacology; D015703:Antigens, CD / Q000032:analysis / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003470:Culture Media / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D015232:Dinoprostone / Q000494:pharmacology; D005434:Flow Cytometry; D005978:Glutathione / Q000494:pharmacology; D006684:HLA-DR Antigens / Q000032:analysis / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010949:Plasma / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D015703:Antigens, CD; D000975:Antioxidants; D003470:Culture Media; D016207:Cytokines; D006684:HLA-DR Antigens; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide; D002374:Catalase; D005978:Glutathione; D015232:Dinoprostone; D000111:Acetylcysteine