特异型性皮炎（AD）是最常见的慢性复发性炎症性皮肤病。它的免疫学异常主要表现为固有免疫抑制，Th1/Th2型免疫失衡，尤其是Th2免疫亢进。本课题组前期研究发现汉族AD患者的皮损处葡萄球菌属相对丰度上升，且金葡菌参与AD发病，与疾病严重度相关。而AD患者皮损处痤疮丙酸杆菌（P. acnes）丰度下降，有报道称P.ances能够缓解AD鼠皮损，确切机制不明。P.acnes又可激活TLR2和TLR4刺激固有免疫，刺激角质形成细胞分泌抗菌肽，诱导Th1免疫应答。本研究旨在：1、提取P.acnes纯化物，观察其对正常人上皮细胞生长的影响及对金黄色葡萄球菌毒素的抑制作用；2、解释P acnes通过TLR2和TLR4激活MyD88-NFκB通路，促进抗菌肽分泌，强化固有免疫机制；3、证实P.acnes纯化物对AD鼠疾病表型的缓解，探讨其中免疫机制。

Atopic dermatitis (AD) is a chronic refractory inflammatory dermatosis with high incidence. AD often present with inhibition of innate immunity, imbalance of Th1/Th2 immunity, especially activation of Th2 immunity. Our group has found the deficiency of skin microbiota in Han AD patients, the abundance ratio of staphylococcus augment. Resently, quiet a mount of studies proved that the S. aureus take part in the pathogenesis of AD and relate to disease severity. On the other side, abundance ratio of propionibacterium ances (P. acnes) decrease in AD lesions. As vaccination of P. acnes improves AD mouse model, but the pathogenesis remained unknown. As the P. acnes is a Th1-response antigen, promotor of innate immunity by TLR2 and TLR4, activator of AMPs secretion by keratinocyte. This study aims to: 1. Find the purification of P. acnes, observe its influence of normal human keratinocytes and inhibition to staphylococcus aureus toxin; 2. Elaborate the mechanism of P. acnes enhancing innate immunity by up-regulating TLR2 and TLR4 and MyD88-NFκB expression, enhancing secretion of AMPs; 3. The purified P. acnes improves AD mouse model, the clinic manifestation, skin histopathology, regulation of innate immunity deficiency and Th1/Th2 imbalance, and finally discovery of a new AD treatment.