title: Heterogeneity of avian gammadelta T cells.
abstract: gammadelta T cells are distinct with respect to tissue localisation, phenotype and biological functions and similarities between species are not very apparent. To elucidate local and functional heterogeneity of non-stimulated avian gammadelta T cells, the CD8-characterised gammadelta T cell subsets [CD8alpha(+high) (CD8alphaalpha(+) and CD8alphabeta(+)); CD8alpha(+dim); CD8(-)] of blood, spleen and caecum were flow cytometrically quantified and analysed for proliferation state as well as sorted for determination of immune-relevant gene expression by quantitative real-time RT-PCR. The number of avian CD8-characterised gammadelta T cell subsets differed in dependence on tissue and age of bird. Compared to blood and spleen, caecum showed the highest percentage of gammadelta T cells as well as of the CD8alpha(+high) gammadelta T cell subset in 7-week-old birds. Generally, the CD8alphabeta(+) cells significantly outnumbered the CD8alphaalpha(+) lymphocytes within the CD8alpha(+high) gammadelta T cell population of all organs. Additionally, the splenic CD8alphabeta(+) subpopulation revealed the highest proliferation activity. By RT-PCR, mRNA expression of immune-relevant genes was proved in non-stimulated gammadelta T cell subsets, but on different levels. Generally, both CD8alpha(+high) cell subsets (CD8alphaalpha(+) and CD8alphabeta(+)) of blood and spleen showed elevated expression levels for Fas ligand (FasL), XCL1 (lymphotactin) and interferon-gamma (IFNgamma) compared to the CD8alpha(-) gammadelta T cell subset. In contrast, all caecal gammadelta T cell subsets showed similar high levels of these transcripts. Notably, the CD8alphaalpha(+) cells of all locations showed unique expression of TLR4 and interleukin (IL)-2. The results demonstrated that avian gammadelta T cells are not only heterogeneous concerning their CD8 antigen characteristics and tissue localisation, but also with regard to functional features such as proliferation and mRNA expression.
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Naumburger Str. 96a, D-07743 Jena, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Pieper
authors.forename: Ulrich
authors.initials: U
authors.lastname: Methner
authors.forename: Angela
authors.initials: A
authors.lastname: Berndt
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000502:physiology*; D002432:Cecum / Q000166:cytology / Q000276:immunology; D002453:Cell Cycle / Q000502:physiology; D002645:Chickens / Q000276:immunology / Q000502:physiology*; D053222:Fas Ligand Protein / Q000096:biosynthesis / Q000235:genetics; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D008222:Lymphokines / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000097:blood / Q000276:immunology / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000096:biosynthesis / Q000235:genetics; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000502:physiology*
chemical_list: D053222:Fas Ligand Protein; D008222:Lymphokines; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta; D012795:Sialoglycoproteins; C018997:lymphotactin; D007371:Interferon-gamma