Study ofSalmonellapathogenicity mechanisms invitroand invivo

Salmonella enterica subsp. enterica includes many pathogenic serovars. Models of the study areS. typhimuriumandS. abortusovis, a restricted serovar to sheep. Bacterial pathogen’s transmission strategies are usually connected to pathogenesis and limited information is available about the immune response of sheep toS. abortusovisand about flagellin interaction withS. abortusovis. Knowledge about those factors are mainly based on studies ofS. typhimurium.Here we try to understand the role of flagella inS. abortusovis. The idea is thatS. abortusovishighly regulates expression of flagella within the host, and we performed studies to clarify howS. abortusovisevade activation of the immune system.Mutations inS. abortusovisflagella genes were generated and flagella from wild type and mutant’s strains of the two different serovars were extracted using diverse media to observe differences in flagellation and host interaction. Samples were analyzed by Western Blot to determine expression of major flagellar protein. Surface expression of flagella was verified by Flow Cytometry and by Scanning Electron Microscopy. To verify the capacity ofS. typhimuriumandS. abortusovisto stimulate TLR5, a colorectal carcinoma cell line (T84 cells) was treated with purified flagellin and the transcriptional induction of a CXC chemokine IL-8 was measured.We showed thatS. abortusovisflagella are expressed in specific media, and they induced the transcription of IL-8 in T84 cells.