The activating rat Ly49s5 receptor responds to increased levels of MHC class Ib molecules on Listeria monocytogenes-infected enteric epithelial cells.
We have investigated whether rat Ly49 receptors can monitor Listeria-infected intestinal epithelial cells through altered expression of MHC class I molecules. The rat colon carcinoma epithelial cell line CC531 infected with Listeria expressed higher levels of both classical and nonclassical MHC-I molecules. Reporter cells expressing the activating Ly49s5 receptor displayed increased stimulatory responses when incubated with Listeria-infected CC531 cells in vitro, which could be blocked with mAb 8G10 specific for nonclassical MHC-I molecules of the RT1(u) haplotype, but not with mAb OX18 reacting with classical MHC-I molecules in this haplotype. Similar responses were observed against IFN-γ-treated cells that also upregulated their expression of MHC-I molecules. Thus, the Ly49s5 receptor can respond to increased levels of nonclassical MHC-I molecules induced on target cells by either bacterial infection or cytokine stimulation. We furthermore found that splenic NK and NKT cells produced IFN-γ in response to Listeria-infected CC531 cells, and that this was not limited to Ly49-expressing cells, since similar levels of IFN-γ production were observed in Ly49(+) and Ly49(-) NK cell subsets. Therefore, NK cells may recognize Listeria-infected cells through both MHC-I-dependent and -independent innate immune receptor systems.
Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway. hamid.shegarfi@medisin.uio.no
Hamid
H
Shegarfi
Ke-Zheng
KZ
Dai
Marit
M
Inngjerdingen
James C
JC
Ryan
John T
JT
Vaage
Bent
B
Rolstad
Christian
C
Naper
D056704:Adaptive Immunity / Q000187:drug effects; D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007113:Immunity, Innate / Q000187:drug effects; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008089:Listeria monocytogenes / Q000276:immunology* / Q000472:pathogenicity; D008088:Listeriosis / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D055650:NK Cell Lectin-Like Receptor Subfamily A / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D055611:Natural Killer T-Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D015854:Up-Regulation / Q000187:drug effects
D019138:Antibodies, Blocking; D015395:Histocompatibility Antigens Class I; D055650:NK Cell Lectin-Like Receptor Subfamily A; D007371:Interferon-gamma