The incorporation of 5-bromo-2'-deoxyuridine (BrdU) into the DNA of active T lymphocytes from healthy aged donors was evaluated after in vitro PHA stimulation by means of light microscopy, electron microscopy and flow cytometry. The percentage of BrdU-labelled cells differed markedly between aged and young donors after 48 h of PHA stimulation, due to an enlarged early S phase compartment. In contrast, after 72 h the percentage of positive cells was quite similar in both age groups and no significant differences in the distribution within S phase nor changes in the patterns of ultrastructural localization of DNA replicon sites were observed. Our study provides evidence that an altered synchronization and a substantial delay in the in vitro cell proliferation occur in this peculiar T subpopulation as a consequence of the ageing process.
Age-related events in active T lymphocyte subpopulation. A morphological study / RANA R.; DI PIETRO R.; CENTURIONE L.; VITALE M.; ZAMAI L.; SCISCIO A.; MAZZOTTI G.. - In: MECHANISMS OF AGEING AND DEVELOPMENT. - ISSN 0047-6374. - 73(1)(1994), pp. 17-25. [10.1016/0047-6374(94)90034-5]