title: Characterization of age-related changes in bovine CD8+ T-cells.
abstract: Evaluation of the changes induced by immunological interventions requires a baseline against which to compare those changes. The age-related changes in the CD8(+) T-cell population of cattle were studied. The results indicate that CD8(+) T-cells could be divided into γ/δ TCR1(+) and γ/δ TCR1(-) according to their expression of the γ/δ T-cell receptor. As a proportion, the CD8(+) γ/δ TCR1(+) population appears to increase with age. Within the CD8(+)γ/δ TCR1(-) a population of cells expressing a profile of surface molecules previously associated with effector memory T cells (CD45RO(+), CD62L(-), CD27(-), CD45RA(-) and CD28(-)) increases with age. Furthermore, a parallel increase with age in the proportion of CD8(+)CD45RO(+) T cells that express the cytotoxic granule protein perforin was observed. In peripheral tissues, namely lungs, it was found that the majority of CD8(+) T cells present expressed a phenotype indicative of previously primed T cells (high expression of CD45RO and perforin). In contrast, only a small population of memory CD8(+) T cells was present in lymphoid tissue where most of the CD8(+) T cells expressed a naïve phenotype. In conclusion, in cattle, like in human, CD8(+) T cells that express a phenotype associated with antigen experience accumulate with age that may play a role in immunocompetence as the individual ages.
authors.affiliation: Institute for Animal Health, Compton, Nr. Newbury, Berkshire, RG20 7NN, UK.
authors.forename: Alison E
authors.initials: AE
authors.lastname: Hogg
authors.forename: Keith
authors.initials: K
authors.lastname: Parsons
authors.forename: Geraldine
authors.initials: G
authors.lastname: Taylor
authors.forename: Andrew
authors.initials: A
authors.lastname: Worth
authors.forename: Peter
authors.initials: P
authors.lastname: Beverley
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Howard
authors.forename: Bernardo
authors.initials: B
authors.lastname: Villarreal-Ramos
mesh_terms: D000375:Aging / Q000097:blood / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000097:blood / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D002417:Cattle / Q000276:immunology*; D005434:Flow Cytometry / Q000662:veterinary; D007156:Immunologic Memory; D017493:Leukocyte Common Antigens / Q000097:blood / Q000378:metabolism; D010641:Phenotype
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D017493:Leukocyte Common Antigens