title: Age-related changes in major lymphocyte subsets in cynomolgus monkeys.
abstract: Age-related changes in major lymphocyte subsets were analyzed in 195 cynomolgus monkeys (Macaca fascicularis) aged from one month to 31 years. The percentages of CD20+ B cells in peripheral blood lymphocytes (PBL) decreased with age to five years of age, but after that, no significant change was observed. The percentages of CD16+ NK cells gradually increased during the first five years and reached the peak at from four to ten years of age, whereas the percentages of CD3+ T cells in PBL were relatively constant throughout the life. Among the T cells, the CD4+ CD8- T cells decreased, but CD4- CD8+ T cells increased within the first decade of life. We further analyzed the expressions of CD28 and CD29 molecules on T cells to determine the relation between age-related activation and phenotypic changes. Almost all CD4+ CD8- T cells (> 90%) were CD28+ at all ages analyzed, but a clear age-related decrease in CD28 expression was demonstrated in CD4- CD8+ T cells during the first ten years. In the case of CD29 expression, age-related increases in CD29hi cells were apparent in both CD4+ CD8- and CD4- CD8+ T cells during the first ten years. The percentages of CD29hi cells, however, were higher in CD4- CD8+ T cells than in CD4+ CD8- T cells in all ages analyzed. These results indicated that the age-related changes in percentages of major lymphocyte subsets as well as in phenotypes of T cells might be related to the maturation of the immune system including an increase in memory cells in cynomolgus monkeys.
authors.affiliation: Tsukuba Primate Center, National Institute of Infectious Diseases, Ibaraki, Japan.
authors.forename: K H
authors.initials: KH
authors.lastname: Nam
authors.forename: H
authors.initials: H
authors.lastname: Akari
authors.forename: K
authors.initials: K
authors.lastname: Terao
authors.forename: S
authors.initials: S
authors.lastname: Itagaki
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikawa
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D018951:Antigens, CD20 / Q000097:blood; D016175:B-Lymphocyte Subsets / Q000276:immunology; D018106:CD28 Antigens / Q000097:blood; D017252:CD3 Complex / Q000097:blood; D016516:CD4-CD8 Ratio; D005260:Female; D019012:Integrin beta1 / Q000097:blood; D007694:Killer Cells, Natural / Q000276:immunology; D016131:Lymphocyte Subsets / Q000276:immunology*; D008252:Macaca fascicularis / Q000276:immunology*; D008297:Male; D017452:Receptors, IgG / Q000097:blood; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D018951:Antigens, CD20; D018106:CD28 Antigens; D017252:CD3 Complex; D019012:Integrin beta1; D017452:Receptors, IgG