近期研究表明，脓毒症死亡的主因是后期免疫抑制引起的继发感染。Foxp3+调节性T细胞（Treg）的异常增多是导致免疫抑制的关键原因。我们前期研究显示，电针可激活交感和迷走神经，在二者协同作用下，调节固有免疫对内毒素的应答。鉴于Foxp3+ Treg表达胆碱能和肾上腺素能受体，且自主神经功能下降时，Foxp3+Treg数目增多，我们推测：脓毒症后期实施电针，可激活交感和（或）迷走神经，减少Foxp3+ Treg，增强对继发感染的抵抗力。本项目拟采用脓毒症后期继发感染军团菌的大鼠模型，观察电针对Foxp3+ Treg、CD4+ T细胞和继发感染的影响，通过Foxp3+ Treg过继转移、膈下迷走神经切断、化学交感阻断等方法，明确Foxp3+ Treg在电针改善免疫抑制中的作用及自主神经介导的调控机制。本项目从神经免疫调节角度阐释电针作用机理，为促进电针在脓毒症治疗中的临床应用提供理论依据。

It has been reported that the vast majority of septic patients do not die due to complications resulting from an overwhelming proinflammatory immune response but due to secondary/opportunistic infections resulting from a severely suppressed immune response in the later phase of sepsis. Recently, accumulating evidence have demonstrated that a significant increase in Foxp3+ Regulatory T cells (Tregs) number and suppressive function makes them an important participant in the sepsis-induced immunosuppression. Our previous study indicated that Electroacupuncture can modulate the response of the innate immune system to endotoxin via activation of both periphery sympathetic and parasympathetic systems. As Foxp3+ Treg cells express adrenergic and acetylcholine receptors, and chemical sympathectomy or vagotomy induces an increase in the number of peripheral Tregs, we hypothesized that in the later phase of sepsis application of Electroacupuncture could decrease the number and function of Foxp3+ Treg cells via activation of sympathetic and/or parasympathetic systems, which may result in enhancing CD4+ T cells proliferation, reducing the levels of bacteria in spleen, and markedly improving survival of L. pneumophila infection. Based on a sepsis surviving rat model which was challenged with secondary pulmonary infection by intranasal inoculation of nonlethal dose of Legionella, we observed the effects of Electroacupuncture on the number and function of Foxp3+ Treg and CD4+ T cells, and susceptibility to L. pneumophila. Also, the key role of Foxp3+ Treg cells modulation mediated by autonomic nervous system in the immune-enhancing effects of Electroacupuncture was determined by Foxp3+ Treg cells adoptive Transfer, chemical sympathectomy, vagotomy, and so on. In this study, we attempted to clarify underlying mechanisms of Electroacupuncture-induced immunostimulation from a neuroimmune perspective, which may provide rationale for the development of Electroacupuncture as a treatment for the sepsis-induced immunosuppression.