title: Micro-RNA 155 is required for optimal CD8+ T cell responses to acute viral and intracellular bacterial challenges.
abstract: Recent studies have begun to define the role of micro-RNAs in regulating the immune response. Micro-RNA155 (mir-155) has been shown to play a role in germinal center formation, T cell inflammation, and regulatory T cell development. In this study, we evaluated the role of mir-155 in cytotoxic T cell function. We report in this study that mice lacking mir-155 have impaired CD8(+) T cell responses to infections with lymphocytic choriomeningitis virus and the intracellular bacteria Listeria monocytogenes. We show by a series of adoptive transfer studies that the impaired CD8(+) T cell response to L. monocytogenes is T cell intrinsic. In addition, we observed that CD8(+) T cells lacking mir-155 have impaired activation of the prosurvival Akt pathway after TCR cross-linking. These data suggest that mir-155 may be a good target for therapies aimed at modulating immune responses.
authors.affiliation: Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, Toronto, Ontario M5G 2C1, Canada.
authors.forename: Evan F
authors.initials: EF
authors.lastname: Lind
authors.forename: Alisha R
authors.initials: AR
authors.lastname: Elford
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Ohashi
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation; D000942:Antigens, Bacterial / Q000276:immunology; D017209:Apoptosis / Q000276:immunology; D060966:Clonal Selection, Antigen-Mediated; D003602:Cytotoxicity, Immunologic; D008088:Listeriosis / Q000276:immunology*; D008216:Lymphocytic Choriomeningitis / Q000276:immunology*; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D010446:Peptide Fragments / Q000276:immunology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000637:transplantation
chemical_list: D000942:Antigens, Bacterial; D035683:MicroRNAs; C532623:Mirn155 microRNA, mouse; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt