Our recent efforts have examined novel activating Ly-49 NK receptors. Murine Ly-49D augments NK cell function upon recognition of target cells expressing H-2Dd. In addition, we demonstrate that Ly-49D receptor ligation can lead to the rapid and potent secretion of IFN-""""""""symbol""""""""g. Cytokine secretion can be induced from Ly-49D+ NK cells after receptor ligation with Ab or after interaction with target cells expressing their H-2Dd ligand. Consistent with the dominant inhibitory function of Ly-49G, NK cells coexpressing Ly-49D and Ly-49G show a profound reduction in IFN-""""""""symbol""""""""g secretion after interaction with targets expressing their common ligand, H-2Dd. As an extension of these studies, we evaluated gene expression upon cross-linking the activating Ly-49D mouse NK receptor in an attempt to understand potential novel functions of these receptors in vivo. Gene expression was evaluated using a microarray from Genome Systems Incorporated (St. Louis, MO). In brief, alterations in gene expression were evaluated Mouse GEM? 1 microarray chip where each chip displays a total of 8,734 elements. Although other genes were identified, the strongly induced genes fell into two categories 1) soluble factors and 2) apoptotic genes. The majority of the mRNAs that were strongly induced as analyzed by microarray hybridization were chemokine genes. Ribonuclease protection assays and chemokine protein production analysis validated the microarray results as activating the Ly-49D mouse NK receptor induced high levels of IFN-""""""""symbol""""""""g, lymphotactin, MIP1""""""""symbol""""""""a and MIP1""""""""symbol""""""""b mRNAs and protein following cross-linking. This gene expression was specific since other chemokines such as KC and MIP-2 were not induced. Although NK cells previously have been shown to respond to chemokines, our data demonstrates that these cells can be strong producers of these inflammatory mediators as well. Thus we conclude that a primary role for the activating NK receptors in vivo is as a trigger for soluble factor production and regulation of the immune response at the site of receptor activation. This would place NK cells and their activating Ly-49 receptors as important initiators of microbial immunity and key elements of the innate immune system.

Agency
National Institute of Health (NIH)
Institute
Division of Basic Sciences - NCI (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC009247-20
Application #
6433136
Study Section
(LEI)
Project Start
Project End
Budget Start
Budget End
Support Year
20
Fiscal Year
2000
Total Cost
Indirect Cost
Name
Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Ortaldo, John R; Winkler-Pickett, Robin T; Bere Jr, Earl W et al. (2005) In vivo hydrodynamic delivery of cDNA encoding IL-2: rapid, sustained redistribution, activation of mouse NK cells, and therapeutic potential in the absence of NKT cells. J Immunol 175:693-9
Ortaldo, John R; Young, Howard A (2005) Mouse Ly49 NK receptors: balancing activation and inhibition. Mol Immunol 42:445-50
Ortaldo, John R; Young, Howard A; Winkler-Pickett, Robin T et al. (2004) Dissociation of NKT stimulation, cytokine induction, and NK activation in vivo by the use of distinct TCR-binding ceramides. J Immunol 172:943-53
Mason, Llewellyn H; Willette-Brown, Jami; Anderson, Stephen K et al. (2003) Receptor glycosylation regulates Ly-49 binding to MHC class I. J Immunol 171:4235-42
Ortaldo, John R; Young, Howard A (2003) Expression of IFN-gamma upon triggering of activating Ly49D NK receptors in vitro and in vivo: costimulation with IL-12 or IL-18 overrides inhibitory receptors. J Immunol 170:1763-9
Raziuddin, A; Bennett, M; Winkler-Pickett, R et al. (2000) Synergistic effects of in vivo depletion of Ly-49A and Ly-49G2 natural killer cell subsets in the rejection of H2(b) bone marrow cell allografts. Blood 95:3840-4
Peacock, C D; Lin, M Y; Ortaldo, J R et al. (2000) The virus-specific and allospecific cytotoxic T-lymphocyte response to lymphocytic choriomeningitis virus is modified in a subpopulation of CD8(+) T cells coexpressing the inhibitory major histocompatibility complex class I receptor Ly49G2. J Virol 74:7032-8
Mason, L H; Willette-Brown, J; Mason, A T et al. (2000) Interaction of Ly-49D+ NK cells with H-2Dd target cells leads to Dap-12 phosphorylation and IFN-gamma secretion. J Immunol 164:603-11
Bosco, M C; Curiel, R E; Zea, A H et al. (2000) IL-2 signaling in human monocytes involves the phosphorylation and activation of p59hck. J Immunol 164:4575-85
Ortaldo, J R; Winkler-Pickett, R; Wiegand, G (2000) Activating Ly-49D NK receptors: expression and function in relation to ontogeny and Ly-49 inhibitor receptors. J Leukoc Biol 68:748-56

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