title: Functional characterization of T cells in abdominal aortic aneurysms.
abstract: Abdominal aortic aneurysms (AAA) exhibit features of a chronic inflammatory disorder. The functional attributes of the T cells in AAA tissue are unclear, with little quantitative or functional data. Using a novel, non-enzymatic method to isolate viable cells from AAA tissue, functional properties of AAA T cells were investigated for the first time. Composition and phenotype of AAA T cells was determined by flow cytometry and verified by immunohistochemistry. Tissue mononuclear cells (MNCs) were cultured in the presence of T-cell mitogens, and cell cycle analysis and cytokine production assessed. Typical cell yield was 4.5 x 10(6) cells per gram of AAA tissue. The majority (58.1+/-5.3%) of haematopoietic (CD45+) cells recovered were CD3+ T cells, B cells comprised 41.1+/-5.7%, natural killer cells 7.3+/-2.5%, and macrophages 2%. Freshly isolated T cells were in resting (G1) state, with 25% expressing the activation-associated cell surface antigens major histocompatibility complex II and CD25. When stimulated in vitro, a significant proportion entered S and G2 phase of the cell cycle, up-regulated CD25, and secreted tumour necrosis factor-alpha, interferon-gamma, interleukin (IL)-5 and IL-6. Despite patient differences, the composition of the AAA inflammatory infiltrate was remarkably consistent, and when re-stimulated ex-vivo T cells produced a stereotypical cytokine response, consistent with the hypothesis that AAA T cells can promote tissue inflammation by secretion of proinflammatory cytokines, and in addition provide signals for B-cell help.
authors.affiliation: School of Biochemistry and Microbiology, University of Leeds, Leeds, UK.
authors.forename: Nerys D
authors.initials: ND
authors.lastname: Forester
authors.forename: Sheena M
authors.initials: SM
authors.lastname: Cruickshank
authors.forename: D Julian A
authors.initials: DJ
authors.lastname: Scott
authors.forename: Simon R
authors.initials: SR
authors.lastname: Carding
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000276:immunology*; D002453:Cell Cycle / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D008213:Lymphocyte Activation / Q000276:immunology; D008211:Lymphocyte Cooperation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008934:Mitogens / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D016207:Cytokines; D008934:Mitogens; D015375:Receptors, Interleukin-2