Effect of high mobility group protein B1 on costimulatory molecules expression of the surface of spleen dendritic cells in rats

Objective To investigate the effect of high mobility group protein B1 (HMGB1) on expression of costimulatory molecules on the surface of spleen dendritic cells (DCs) and its potential reg- ulating mechanism in rats.Methods DCs isolated from the spleens of male Wistar rats were seeded on 96-well (1×10~5 cells/well) cell culture plates,and the cells were stimulated with HMGB1 for various lengths of time and in different concentrations.After being stimulated,DCs were denatured in cell culture plates to determine the expressions of costimulatory molecules including CD80,CD86 and major histocom- pability complex (MHC)Ⅱ.The time-dependent and dose-dependent responses between HMGB1 and costimulatory molecules CD80,CD86 and MHCⅡexpressions were analyzed by flow cytometry.Re- sults After stimulating with 1μg/ml HMGB1,the expressions of the costimulatory molecules CD80, CD86 and MHCⅡon the surface of rat spleen DCs were markedly up-regulated at 24 to 72 hours (P＜0.05 or P＜0.01),and the expression levels of CD80,CD86 and MHCⅡpeaked at 48 hours (P＜0.01).When DCs were cultured in the presence of 0.1μg/ml,1μg/ml,and 10μg/ml HMGB1 for 48 hours,the expressions of the costimulatory molecules CD80,CD86 and MHCⅡwere significantly up-regu- lated (P＜0.05 or P＜0.01 ),and the values of these three molecules were the highest in the 1μg/ml HMGB1-treated group (P＜0.01).Conclusion HMGB1 stimulation can result in marked up-regula- tion of expressions of costimulatory molecules,CD80,CD86 and MHCⅡon the surface of rat spleen DCs,and HMGB1 appears to be a potential immunostimulatory signal that induces DC maturation.