ALBERT

Description:    Salmonella enterica serovar Typhi ( S. typhi ) evades from innate immunity by expression of a variety of pathogenic factors. The “pR ST98 ” plasmid of S. typhi is involved in multidrug-resistant and virulence of S. typhi . However, its exact effect on host cell function remains elusive. Dendritic cells (DCs) play an important role in shaping immune response against Salmonella . For the purpose of investigation whether pR ST98 might target DCs involved in adaptive immune response, murine DCs were infected with S. typhi wild type and mutant strains. S. typhi stimulation resulted in up-regulation of costimulatory molecules on DCs. S. typhi wild type resulted in decreased up-regulation of CD40, CD80, and CD86 expression. Experiments with S. typhi pR ST98 mutant ( S. typhi -Δ-pR ST98 ) and S. typhi -Δ-pR ST98 with a complemented plasmid encoding pR ST98 ( S. typhi -c-pR ST98 ) revealed that pR ST98 accounts for inhibition of surface molecule expression and functional maturity. S. typhi -Δ-pR ST98 gave maximal levels of IL-12 and IFN-γ release compared with wild type S. typhi or the complemented strains. In contrast to IL-12 and IFN-γ, IL-10 secretion by S. typhi -Δ-pR ST98 -infected DCs was significantly lower than induction by S. typhi wild type. This indicates that immunity in response to pR ST98 is skewed away from a protective Th1 response. Moreover, infection with S. typhi -Δ-pR ST98 induced autophagy in DCs. We herein demonstrate S. typhi pR ST98 plays essential roles in modulating DCs maturation, activation, inflammatory responses, and autophagy. Together, these data prove that pR ST98 targets functions of DCs that are required for T-cell activation. This might contribute to evasion of adaptive immune responses by S. typhi . Content Type Journal Article Pages 1-8 DOI 10.1007/s00284-012-0136-1 Authors Li Wei, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123 Jiangsu, People’s Republic of China Shuyan Wu, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123 Jiangsu, People’s Republic of China Yuanyuan Li, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123 Jiangsu, People’s Republic of China Yuanyuan Chu, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123 Jiangsu, People’s Republic of China Rui Huang, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123 Jiangsu, People’s Republic of China Journal Current Microbiology Online ISSN 1432-0991 Print ISSN 0343-8651