Research on mechanisms of mononuclear phagocyte in response to Salmonella typhi strains

  Objective   To research the mechanisms of mononuclear phagocyte in response to Salmonella typhi strains.

  Methods   The activities of internalization and intracellular survival of S.typhi strains, as well as the production of TNF-A and IL-12 induction by S.typhi strains were detected by using PMA differentiated THP-1 cells cultured in vitro.

  Results   Vi negative S.typhi strains were internalized and killed significantly by PMA differentiated THP-1 cells by contrast to V_i positive S.typhi strains.The activities of PMA differentiated THP-1 cells werer enhanced dramatically by IFN-C.The results also showed that the production of TNF-A and IL-12 can be induced by S.typhi strains in PMA differentiated THP-1 cells.However, the productive amount of TNF-A and IL-12 was significantly increased in PMA differentiaed THP-1 cells activated by IFN-C.

  Conclusion   The survial of S.typhi strains inside mononuclear phagocytes might be related to the presence of V_i antigen.Moreover, IFN-C played an important role in the regulation of the cellular immunity of immune system against S.typhi infection.