title: Reconstitution models to evaluate natural killer T cell function in tumor control.
abstract: Natural killer T (NKT) cells are glycolipid-reactive T lymphocytes that function in immunosurveillance and immune regulation. However, reduced tumor control in NKT cell-deficient Jα18(-/-) mice may be confounded by an overall reduction in T-cell receptor (TCR) repertoire diversity in these animals. Mechanistic studies are also hindered by a lack of tools to target molecules specifically in NKT cells. To address these issues, we developed protocols to expand functional NKT cells and stably reconstitute them in Jα18(-/-) mice. In vivo delivery of α-galactosylceramide (α-GalCer)-loaded dendritic cells expanded NKT cells in wild-type mice without skewing CD4 or TCR Vβ expression profiles. Expanded NKT cells exhibited enhanced cytokine responses upon re-stimulation with glycolipid or CD3 ligation. Adoptive transfer of recently expanded wild-type or interferon (IFN)-γ(-/-) NKT cells protected recipient Jα18(-/-) mice from B16 melanoma metastasis without the need for additional glycolipid stimulation. However, NKT cell reconstitution in recipient Jα18(-/-) mice was short lived. Long-term reconstitution was only achieved when expanded NKT cells were transferred into sublethally irradiated recipients. Thirty days after transfer, NKT cell numbers, phenotype and α-GalCer-induced cytokine responses were equivalent to naive wild-type mice. Jα18(-/-) recipients reconstituted with wild-type or IFN-γ(-/-) NKT cells were both protected from B16 melanoma metastasis following α-GalCer treatment, and NK cell transactivation was intact in mice reconstituted with IFN-γ(-/-) NKT cells. These studies validate the use of reconstitution protocols to investigate the mechanisms of NKT cell immune function, demonstrating that NKT cell-derived IFN-γ and the altered TCR repertoire in Jα18(-/-) mice do not impact NKT cell-mediated antitumor responses.
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.|Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Gebremeskel
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Drew
authors.initials: D
authors.lastname: Slauenwhite
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.|Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada.|Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.|Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada.
authors.forename: Brent
authors.initials: B
authors.lastname: Johnston
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology; D005699:Galactosylceramides; D007371:Interferon-gamma / Q000172:deficiency / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D008546:Melanoma, Experimental / Q000276:immunology* / Q000473:pathology*; D008810:Mice, Inbred C57BL; D018448:Models, Immunological; D055611:Natural Killer T-Cells / Q000276:immunology*; D010641:Phenotype; D015533:Transcriptional Activation
chemical_list: D015415:Biomarkers; D005699:Galactosylceramides; C493154:alpha-galactosylceramide; D007371:Interferon-gamma