The rat NK cell receptors Ly49s4 and Ly49i4 recognize nonclassical MHC-I molecules on Listeria monocytogenes-infected macrophages.
Ly49 receptors in rodents, like KIRs in humans, regulate NK cell activity. Although inhibitory Ly49 receptors clearly recognize MHC-I molecules, ligands for the activating Ly49 receptors are less well defined. Here, we show that the activating Ly49s4 and the inhibitory Ly49i4 receptors recognize nonclassical MHC-I molecules on the rat macrophage cell line R2 (RT1(d)). Listeria infection of R2 macrophages led to increased expression of classical and nonclassical MHC-I molecules. Coincubation of these infected cells with reporter cells expressing Ly49i4 or Ly49s4 increased the reporter cell responses. These responses were blocked by mAb OX18 (anti-MHC-I) and AAS1 (anti-nonclassical MHC-I). IFN-γ treatment of normal R2 cells also increased the MHC-I expression and enhanced the reporter cell responses. These results suggest that activating and inhibitory Ly49 receptors monitor MHC-I expression on Listeria-infected cells.
Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway.
Hamid
H
Shegarfi
Ke-Zheng
KZ
Dai
Michael R
MR
Daws
James C
JC
Ryan
John T
JT
Vaage
Bent
B
Rolstad
Christian
C
Naper
D000818:Animals; D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000950:Antigens, Ly / Q000276:immunology*; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology* / Q000382:microbiology; D008089:Listeria monocytogenes / Q000502:physiology*; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology*; D051381:Rats; D055607:Receptors, Natural Killer Cell / Q000276:immunology*
D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D015395:Histocompatibility Antigens Class I; D055607:Receptors, Natural Killer Cell