Rescigno Maria, Urbano Matteo, Rimoldi Monica, Valzasina Barbara, Rotta Gianluca, Granucci Francesca, Ricciardi-Castagnoli Paola
Department of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza della Scienza 2, I-20126 Milan, Italy.
Eur J Immunol. 2002 Oct;32(10):2800-6. doi: 10.1002/1521-4141(2002010)32:10<2800::AID-IMMU2800>3.0.CO;2-5.
Toll-like receptor 4 (TLR4) has been recently associated with cellular responses to lipopolysaccharide (LPS), and mice mutated in tlr4, such as C57BL/10ScCr or C3H/HeJ mice, become hyporesponsive to LPS. In this study, we have analyzed the capacity of bone marrow-derived dendritic cells (BMDC) from C57BL/10ScCr (ScCr-BMDC) or C3H/HeJ (HeJ-BMDC) mice to respond to LPS or to Gram-negative bacteria. We show that ScCr- or HeJ-BMDC are insensitive to LPS, but can mature in response to live and killed Gram-negative bacteria. Interestingly, only ScCr-BMDC but not HeJ-BMDC, stimulated with bacteria, have reduced capacity to produce pro- and anti-inflammatory cytokines as compared to BMDC from control mice, probably due to genetic defects unrelated to the tlr4 mutation. Nevertheless, ScCr-BMDC and ScCr BM-macrophages (BM-Mphi) phagocytose Salmonella typhimurium similarly to control cells, indicating that TLR4 is not compulsory for bacterial uptake. Moreover, BM-Mphi, but not BM-DC from B10ScCr or C3H/HeJ mice, are impaired in their capacity to kill intracellular bacteria and to produce NO as compared to wild type controls. However, the bacteria killing property of BM-Mphi is completely restored by pretreating the cells with IFN-gamma. Hence, TLR4 plays different roles in DC versus Mphi.
Toll样受体4（TLR4）最近被认为与细胞对脂多糖（LPS）的反应有关，而在tlr4基因发生突变的小鼠，如C57BL/10ScCr或C3H/HeJ小鼠，对LPS的反应性降低。在本研究中，我们分析了来自C57BL/10ScCr（ScCr-BMDC）或C3H/HeJ（HeJ-BMDC）小鼠的骨髓来源树突状细胞（BMDC）对LPS或革兰氏阴性菌的反应能力。我们发现ScCr-BMDC或HeJ-BMDC对LPS不敏感，但能对活的和灭活的革兰氏阴性菌产生成熟反应。有趣的是，与对照小鼠的BMDC相比，仅受细菌刺激的ScCr-BMDC而非HeJ-BMDC产生促炎和抗炎细胞因子 的能力降低，这可能是由于与tlr4突变无关的基因缺陷所致。然而，ScCr-BMDC和ScCr骨髓巨噬细胞（BM-Mphi）吞噬鼠伤寒沙门氏菌的能力与对照细胞相似，表明TLR4并非细菌摄取所必需。此外，与野生型对照相比，来自B10ScCr或C3H/HeJ小鼠的BM-Mphi而非BM-DC杀伤细胞内细菌和产生NO的能力受损。然而，通过用γ干扰素预处理细胞，BM-Mphi的细菌杀伤特性可完全恢复。因此，TLR4在树突状细胞和巨噬细胞中发挥不同作用。
