Identification of Salmonella typhimurium genes responsible for interference with peptide presentation on MHC class I molecules: Δ yej Salmonella mutants induce superior CD8+ T-cell responses

Udi Qimron, Neta Madar, Hans Willi Mittrücker, Alon Zilka, Ido Yosef, Noga Bloushtain, Stefan H.E. Kaufmann, Ilan Rosenshine, Ron N. Apte, Angel Porgador*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Salmonella-derived epitopes are presented on MHC molecules by antigen-presenting cells, and both CD4+ and CD8+T cells participate in protective immunity to Salmonella. Therefore, mechanisms that allow Salmonella to escape specific immune recognition are likely to have evolved in this bacterial pathogen. To identify Salmonella genes, which potentially interfere with the MHC class I (MHC-I) presentation pathway, Tn10d transposon mutagenesis was performed. More than 3000 mutants, statistically covering half of the Salmonella genome, were individually screened for altered peptide presentation by infected macrophages. Two mutants undergoing enhanced antigen presentation by macrophages were identified, carrying a Tn10d insertion in the yej operon. This phenotype was validated by specific inactivation and complementation experiments. In accordance with their enhanced MHC-I presentation phenotype, we showed that (i) specific CD8+ T cells were elicited at a higher level in mice, in response to immunization with yej mutants compared to their parental strain in two different experimental settings; and (ii) yej mutants were superior vaccine carriers for heterologous antigens compared to the parental strain in a tumour model.

Original languageAmerican English
Pages (from-to)1057-1070
Number of pages14
JournalCellular Microbiology
Volume6
Issue number11
DOIs
StatePublished - Nov 2004

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