Toll-like receptor 2 contributes to liver injury by Salmonella infection through Fas ligand expression on NKT cells in mice.
OBJECTIVE
Toll-like receptors (TLRs) for bacterial constitutes are expressed not only by phagocytes but also by some subsets of T cells. We previously reported that natural killer T cells (NKT cells) play an important role in liver injury induced by Salmonella infection. In the present study, we investigated whether TLRs on NKT cells are involved in Salmonella-induced liver injury.


METHODS
Gene expression of TLR2 was examined in sorted natural killer, NKT, and T cells from livers of naive mice by the reverse-transcription polymerase chain reaction method. Serum alanine aminotransferase level and FasL expression on liver lymphocytes were examined in TLR2-deficient (TLR2(-/-)) and FasL-deficient gld/gld mice before and after intraperitoneal inoculation of Salmonella choleraesuis 31N-1 using an enzyme-linked immunosorbent assay and flow cytometry.


RESULTS
TLR2 gene was abundantly expressed by NKT cells freshly isolated from naive mice. FasL expression on liver NKT cells increased in TLR2(+/-) mice but not in TLR2(-/-) mice after Salmonella infection. Serum alanine aminotransferase level was significantly lower in the TLR2(-/-) and gld/gld mice than in the control mice after infection.


CONCLUSIONS
TLR2 may contribute to liver injury induced by Salmonella infection via FasL induction on liver NKT cells.
D000818:Animals; D016207:Cytokines / Q000235:genetics; D029721:Drosophila Proteins; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D008099:Liver / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism*; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors
D016207:Cytokines; D029721:Drosophila Proteins; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors