Identification of Salmonella typhimurium genes responsible for interference with peptide presentation on MHC class I molecules: Deltayej Salmonella mutants induce superior CD8+ T-cell responses.
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.
Qimron
Udi
U
Department of Microbiology and Immunology, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel.
Madar
Neta
N
Mittrücker
Hans-Willi
HW
Zilka
Alon
A
Yosef
Ido
I
Bloushtain
Noga
N
Kaufmann
Stefan H E
SH
Rosenshine
Ilan
I
Apte
Ron N
RN
Porgador
Angel
A
D000818:Animals; D017951:Antigen Presentation; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation; D009876:Operon; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D022562:Salmonella Vaccines / Q000008:administration & dosage / Q000276:immunology; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D014611:Vaccination
D001426:Bacterial Proteins; D015395:Histocompatibility Antigens Class I; D011948:Receptors, Antigen, T-Cell; D022562:Salmonella Vaccines