title: High frequencies cytomegalovirus pp65(495-503)-specific CD8+ T cells in healthy young and elderly Chinese donors: characterization of their phenotypes and TCR Vbeta usage.
abstract: Human cytomegalovirus (HCMV) is a ubiquitous beta-herpesvirus which persists lifelong after primary infection and can lead to a significant disease in the immunocompromised individuals. CD8(+) T cells are believed to play a crucial role in both the elimination of active infection and maintenance of HCMV latency. Large expansions of CD8(+) T cells specific for a single epitope of HCMV have been well documented in Caucasoid population. To date, no similar study has been performed in Chinese populations. Here we report the characteristics of HCMV-specific CD8(+) T cells in healthy young and elderly Chinese donors using pp65(495-503)-loaded HLA-A*0201 tetramers. Cells were stained with a combination of the tetramers and antibodies for CD28 and CD57 or a panel of TCR Vbeta and analyzed by three-color flow cytometry. The frequencies of pp65(495-503)-specific T cells within total CD8(+) T cell population were between 0.14 and 6.84% (mean 2.45%) in the young donors and were from 0.33 to 6.89% (mean 1.95%) in the elderly donors, respectively. There was no significant difference between the two groups. The expression of CD28 was decreased whereas CD57 expression was increased in tetramer-negative CD8(+) T cells in the elderly when compared with the young group. However, neither of these changes was found within tetramer-positive cell populations. Moreover, TCR Vbeta usage within tetramer-positive population was predominated by certain TCR Vbeta subsets. These results demonstrate that large expansions of HCMV-specific CD8(+) T cells with certain subsets TCR Vbeta exist both in the healthy young and in the elderly Chinese individuals, which may play a role in the maintenance of virus latency but have potential detrimental influence on the immune responses to other pathogens or vaccinations.
authors.affiliation: Institute of Tissue Transplantation and Immunology, College of Life Science and Technology, Jinan University, 601 Huangpu Dadao West, Guangzhou 510632, People's Republic of China. thexh@jnu.edu.cn
authors.forename: Xian-Hui
authors.initials: XH
authors.lastname: He
authors.forename: Qing-Bing
authors.initials: QB
authors.lastname: Zha
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Xu
authors.forename: Xiao-Yun
authors.initials: XY
authors.lastname: Chi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D044466:Asian People; D018106:CD28 Antigens / Q000096:biosynthesis; D018959:CD57 Antigens / Q000096:biosynthesis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003587:Cytomegalovirus / Q000502:physiology; D003586:Cytomegalovirus Infections / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D008297:Male; D010641:Phenotype; D010750:Phosphoproteins / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000276:immunology*; D017735:Virus Latency
chemical_list: D018106:CD28 Antigens; D018959:CD57 Antigens; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D010750:Phosphoproteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D014763:Viral Matrix Proteins; C065418:cytomegalovirus matrix protein 65kDa