title: In vivo imaging of CD8+ T cell-mediated elimination of malaria liver stages.
abstract: CD8(+) T cells are specialized cells of the adaptive immune system capable of finding and eliminating pathogen-infected cells. To date it has not been possible to observe the destruction of any pathogen by CD8(+) T cells in vivo. Here we demonstrate a technique for imaging the killing of liver-stage malaria parasites by CD8(+) T cells bearing a transgenic T cell receptor specific for a parasite epitope. We report several features that have not been described by in vitro analysis of the process, chiefly the formation of large clusters of effector CD8(+) T cells around infected hepatocytes. The formation of clusters requires antigen-specific CD8(+) T cells and signaling by G protein-coupled receptors, although CD8(+) T cells of unrelated specificity are also recruited to clusters. By combining mathematical modeling and data analysis, we suggest that formation of clusters is mainly driven by enhanced recruitment of T cells into larger clusters. We further show various death phenotypes of the parasite, which typically follow prolonged interactions between infected hepatocytes and CD8(+) T cells. These findings stress the need for intravital imaging for dissecting the fine mechanisms of pathogen recognition and killing by CD8(+) T cells.
authors.affiliation: Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Cockburn
authors.forename: Rogerio
authors.initials: R
authors.lastname: Amino
authors.forename: Reka K
authors.initials: RK
authors.lastname: Kelemen
authors.forename: Scot C
authors.initials: SC
authors.lastname: Kuo
authors.forename: Sze-Wah
authors.initials: SW
authors.lastname: Tse
authors.forename: Andrea
authors.initials: A
authors.lastname: Radtke
authors.forename: Laura
authors.initials: L
authors.lastname: Mac-Daniel
authors.forename: Vitaly V
authors.initials: VV
authors.lastname: Ganusov
authors.forename: Fidel
authors.initials: F
authors.lastname: Zavala
authors.forename: Robert
authors.initials: R
authors.lastname: Ménard
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure*; D002460:Cell Line; D018984:Epitopes, T-Lymphocyte / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008099:Liver / Q000276:immunology* / Q000469:parasitology; D008288:Malaria / Q000276:immunology* / Q000469:parasitology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D018613:Microscopy, Confocal / Q000379:methods; D018448:Models, Immunological; D059208:Parasite Load; D010961:Plasmodium / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059008:Time-Lapse Imaging / Q000379:methods
chemical_list: D018984:Epitopes, T-Lymphocyte; D011948:Receptors, Antigen, T-Cell; D049452:Green Fluorescent Proteins
keywords: Plasmodium; immunity; lymphocytes