title: Monitoring of local CD8β-expressing cell populations during Eimeria tenella infection of naïve and immune chickens.
abstract: The purpose of this study was to monitor abundance and activation of local CD8β-expressing T-cell populations during Eimeria tenella infections of naïve chickens and chickens immune by previous infections. Chickens were infected with E. tenella up to three times. Caecal T-cell receptor (TCR) γ/δ-CD8β+ cells (cytotoxic T lymphocytes; CTL) and TCRγ/δ+CD8β+ cells were characterized with respect to activation markers (blast transformation, CD25 and cell surface CD107a). Cells were also induced to degranulate in vitro as a measure of activation potential. Major findings included a prominent long-lasting, up to 6 weeks, increase in the proportion of CTL among caecal CD45+ cells in the later stages after primary E. tenella infection. These CTL also showed clear signs of activation, that is blast transformation and increased in vitro induced degranulation. At second and third E. tenella infection, chickens showed strong protective immunity but discrete signs of cellular activation were observed, for example increased in vitro induced degranulation of CTL. Thus, primary E. tenella infection induced clear recruitment and activation of local CTL. Upon subsequent infections of strongly immune chickens cellular changes were less prominent, possibly due to lower overall numbers of cells being activated because of the severe restriction of parasite replication.
authors.affiliation: Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Wattrang
authors.affiliation: Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Thebo
authors.affiliation: Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lundén
authors.affiliation: Department of Animal Science, Aarhus University, Tjele, Denmark.
authors.forename: T S
authors.initials: TS
authors.lastname: Dalgaard
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000378:metabolism*; D002645:Chickens / Q000276:immunology* / Q000469:parasitology; D003048:Coccidiosis / Q000276:immunology / Q000662:veterinary*; D016786:Eimeria tenella / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D052118:Lysosomal-Associated Membrane Protein 1 / Q000378:metabolism; D011201:Poultry Diseases / Q000276:immunology* / Q000469:parasitology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D016827:CD8 Antigens; C477867:CD8beta antigen; D052118:Lysosomal-Associated Membrane Protein 1; D016692:Receptors, Antigen, T-Cell, gamma-delta
keywords: CD107a; CD25; CD8β; Eimeria tenella; blast transformation; chicken