[ ABSTRACT] AIM:To investigate the molecular mechanism and the immunosuppressive phenotype of macropha-ges under long-term exposure to lipopolysaccharide ( LPS) .METHODS:We used Ficoll-Hypaque density gradient centri-fugation combined with MicroBeads Separation Kits to separate peripheral blood mononuclear cells from human blood, and then induced the monocytes into macrophages.We observed the morphology of the macrophages by treating the cells with LPS for 48 h, in comparison with a negative control and IFN-γtreatment.ELISA was used to detect the levels of cytokines, such as IL-10, IL-12, IL-6 and TNF-α, and flow cytometry was used to detect the expression of the surface molecules (HLA-DR, CD14, CCR7, HLA-ABC and CD40).To observe the effect of macrophage on T cell proliferation, co-culture experiment was carried out for 6 d.Real-time PCR was used to validate the expression levels of molecules related to MyD88-independent pathway in Toll-like receptor 4 ( TLR4) signal pathway.RESULTS:The antigen-presenting ability of the macrophages was reduced and the IL-10 expression level was increased after the cells were treated with LPS for 48 h. We observed a poor proliferative capacity of CD8 +T cells after co-culturing of LPS-induced macrophages with CD3+T cells for 6 d.The results of real-time PCR indicated that TRIF, IRF3 and CIITA were down-regulated in LPS-induced macropha-ges.CONCLUSION:We successfully established a macrophage model in vitro and observed that LPS-induced macropha-ges into an immunosuppressive phenotype with poor CD8 +T cell proliferative capacity, in which MyD88-independent TLR4 signaling pathway was impaired.

Objective This study is to explore the association between self-differentiation and men-tal health among medical students. Methods Differentiation of self inventory-revised (DSI-R) and univer-sity personality inventory (UPI) were used to measure the self-differentiation and mental health of 526 med-ical students from Grade One to Grade Five at a comprehensive university in Shanghai. Result The mean score of DSI-R was (171.25±19.65). 32.2％ of participants had different levels of mental health prob-lems. Female students got higher score of DSI-R than male students (P=0.007). Statistically significant dif-ferences of medical students' self-differentiation were found among years of school attended (P=0.039). Sta-tistically significant differences of self-differentiation were also found between the first class and the third class of UPI (P<0.001) as well as the second class and the third class of UPI (P=0.004). Ordinal regression analysis indicated that self-differentiation was a risk factor for medical students' mental health (OR=1.036, P=0.000). Conclusion The average score of medical students' self-differentiation was higher than college students of other specialties. But their mental health condition was worse. Medical students with higher self-differentia-tion had worse mental health situation.