AGE-DEPENDENT REMODELING OF PERIPHERAL-BLOOD CD4(-LYMPHOCYTES IN CYNOMOLGUS MONKEYS() CD8(+) T)

Recently, we have found in adult cynomolgus monkeys that substantial p eripheral blood CD4(+) CD8(+) double-positive (DP) T lymphocytes exhib it a resting memory phenotype and increase in proportion with age. In this study, we investigated whether phenotypic changes occur in the co urse of the increase in proportion of the DP T cells. The results obta ined from 195 clinically healthy monkeys aged from 1 month to 31 years showed that the CD29(hi) and CD28(-) subpopulation in the DP T subset increased in proportion with age and that the increase reached a plat eau at six years old for the CD29(hi) subpopulation and at eleven year s old for the CD28(-) one, respectively. The phenotypic alteration pre ceded the abrupt increase in proportion of the DP T cells and was able to be classified into four phases on the basis of the qualitative and quantitative alteration. (C) 1998 Elsevier Science Ltd. All rights re served.