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 Home > Available Issues |
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 Original Articles |
| Expression of Toll-like Receptors on the Macrophages Activated by
Bacterial Superantigens |
| Hyo Youl Kim, M.D.1, Hyun Chul Cho, M.S.2, Soo Kie Kim, M.D.2, and Kye Chul Shin, M.D.1 |
| Department of Internal Medicine1, Department of Microbiology2, Wonju College of Medicine, Yonsei University, Wonju, Korea |
Vol.36 Num.5 (p286~293)
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Background:Staphylococcal enterotoxin B (SEB) as a prototype superantigen is known to play a pivotal role in toxic shock syndrome and severe sepsis. However, the precise mechanism initiating the activation of innate effector cells by SEB is unclear. Recently, Toll-like receptors (TLRs), the sensor of pathogen associated molecular pattern (PAMP), have been reported to be expressed abundantly in monocytic lineage-cells. The purpose of this study is to investigate whether TLRs are involved in the SEB-induced immune cell activation and to prove the differential TLRs expression in response to SEB and/or lipopolysaccharide (LPS).
Materials and Methods:SEB was purified by dye ligand affinity chromatography. The mRNA expression of TLR1-9 in human peripheral blood mononuclear cells (PBMC) and human monocyte- like THP-1 cell line stimulated by SEB and/or LPS was detected by RT-PCR.
Results:The treatment of PBMC with SEB elicited significant changes in the expression of several TLRs. Interestingly, the mRNAs of TLR1 and TLR5 were clearly up-regulated in PBMC, whereas mRNA of TLR4 was down-regulated in the very early period of stimulation within 1-2 hours, and subsequently up-regulated 3 hours later after the stimulation. The up-regulation of mRNA of TLR4 was detected in PBMC stimulated by LPS. The up-regulation was more prominent in the cells exposed concomitantly to SEB and LPS. The mRNA expression pattern of TLR4 in THP-1 cell line stimulated by SEB or LPS was comparable to those of PBMC.
Conclusion:This study indicates that SEB triggers inflammatory signals on macrophages and PBMC by engaging TLRs, particularly TLR4. The combination of LPS and SEB synergistically modulates TLR4 signaling. |
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Keywords : Toll-like receptor, Superantigen, Staphylococcal enterotoxin B |
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