CD14-dependent and independent pathways in B cells activation after stimulation with lipopolysaccharides from periodontopathic bacteria

在这项研究中，我们评估了CD14在牙周病细菌脂多糖刺激后B细胞活化中的可能作用。然后，我们研究了内毒素诱导的信号转导机制，该机制介导了B细胞后来的细胞反应。结果表明，CD14不局限于髓系细胞，参与了某些细胞的活化，并与脂多糖诱导的CDK、转化生长因子-β-α的表达增强以及与产生IgA的B细胞不同的同型分化有关。然而，在脂多糖诱导的B细胞活化中也可能存在CD14非依赖性途径，最终导致B细胞的增殖、IL-6的产生和IgM(而不是IgA)分泌的增加。研究还表明，牙龈卟啉单胞菌以及其他牙周病细菌、中间普氏杆菌、伴生放线放线杆菌和腐蚀性艾肯氏杆菌的内毒素可以通过酪氨酸和苏氨酸磷酸化途径传递触发信号，并诱导B细胞激活，最终导致B细胞增殖。综上所述，本研究结果提示，牙周病细菌来源的LPS具有通过CD14依赖和独立的激活途径诱导B细胞刺激的强大特性，其中酪氨酸和苏氨酸磷酸化的增加可能是导致细胞反应的重要信号事件。

In this study we assessed the possible role of CD14 in B cells activation after stimulation with lipopolusaccharides from periodontopathic bacteria. We then examined the LPS-induced signal transduction mechanism that mediates later cellular responses of B cells. The results indicated that CD14 not restricted to myeloid dells, and was involved in some cellular activations and the isotype differentation to IgA-producing B cell to the enhanced expression of CDK TGF-β- production and the isotype different to IgA-producing B cells elicited by LPS. However, CD14-independent pathway could be also exist in the LPS-induced activation of B cells that eventually leads to proliferation, IL-6 production and the enhancement of IgM (but not IgA) secretion. It was also indicated that a trigger signal by the LPS from porphyromonas gingivalis as well as other periodontopathic bacteria, prevotella intermedia, Actinobacillus actinomycetemcomitans and Eikenella corrodens, could be transduced through both tyrosine and threonine phosphorylation pathways, and induced the activation of B cells that eventually leads to proliferation. Taken together, the present findings suggest to the LPSs from periodontopathic bacteria have a potent property to induce the stimulate of B cells through the CD14-dependent and independent activation pathways, in which increased tyrosine and threonine phosphorylation could be important signaling events that might lead to cellular responses.