Interaction of host and bacterium in acute infection

1.肺炎支原体感染诱导的抗菌肽分析小鼠鼻内感染肺炎支原体，24小时后取肺泡灌洗液。BALF中渗出细胞数增加，24 h达高峰，72 h恢复至本底水平，90%为中性粒细胞(PMN)。免疫组织化学染色显示细胞胞浆内含有抗菌素家族成员抗菌肽Cram，经热灭活肺炎支原体作用于人呼吸道上皮细胞EBC-1，可诱导HBD-2基因的表达。此外，在体外实验系统中，HBD-2显示出对肺炎支原体的抗菌活性。肺炎支原体A型脂蛋白是从肺炎支原体中分离得到的，它是FOF1-型ATPase b亚基的一种亚基。该脂蛋白是一种具有两个棕榈酸酯的二酰化蛋白质。脂蛋白传递的细胞信号依赖于TLR1、TLR2和TLR6。类似地，分离出了具有类似能力的三酰化脂蛋白。有趣的是，这些蛋白的信号传递依赖于TLR1和TLR2。在体内，合成脂肽FAM20(FOF1型ATPase a亚单位b亚单位的部分合成脂肽FAM20)可诱导TLR4-KO小鼠和野生小鼠的腹膜渗出细胞产生肿瘤坏死因子-α，但不能诱导TLR2-KO小鼠产生肿瘤坏死因子-ATPase，表明这种产生明显是TLR2依赖的。小鼠肺泡灌洗液中可明显分泌炎性细胞因子α和IL-6。FAM20诱导炎性细胞因子产生的能力略高于三酰化脂肽。同样，在BALF中也产生趋化因子。特别是，MIP-2在刺激后几个小时就产生了。

1. Analysis of anti-microbial peptides induced by mycoplasma infectionMice were intranasally infected with M. pneumoniae and 24 h later the bronchoalveolar lavage fluid (BALF) of the mice were obtained. Number of exudate cells in the BALF was increased with a peak at 24 h and back to the background level at 72 h. 90% of exudate cells was found to be polymorphonuclear leukocyte (PMN). The cells contained antimicrobial peptide CRAMP, a member of cathelicidin family, in cytoplasm, based on immunostaining.When a human airway epithelial cell EBC-1 was treated with heat-inactivated M. pneumoniae, hBD-2 mRNA was induced. Moreover, in vitro in an experimental system, hBD-2 showed antimicrobial activity against M. pneumoniae.2. Purification of lipoproteins, responsible for induction of inflammation, derived from M. pneumoniaeA lipoprotein, a subunit b of FOF1-type ATPase, was isolated from M pneumoniae. The lipoprotein was found to be a diacylated protein with two palmitates. The cell signaling delivered by the lipoprotein was dependent on TLR1, TLR2, and TLR6. Similarly, triacylated lipoproteins with comparable ability were isolated. Interestingly, the signaling by these proteins was TLR1-and TLR2-dependent.3. In vivo induction of inflammation by synthetic lipopeptidesFAM20, a partially synthetic lipopeptide of the a subunit b of FOF1-type ATPase induced the production of TNF-α in peritoneal exudate cells (PEC) of TLR4-KO mice and wild mice, but not TLR2-KO mice, indicating that the production was clearly TLR2-dependent.Subsequently, two different synthetic lipopeptides were administered intranasally to mice. In BALF of the mice, inflammatory cytokines such as TNF-α and IL-6 were markedly secreted. The ability of FAM20 to induce the production of inflammatory cytokines was somewhat higher than that of triacylated lipopeptides. Similarly, chemokines were produced in the BALF. In particular, MIP-2 was produced as early as several hours after stimulation.