Decreased proliferative capability of CD4(+) cells of elderly people is associated with faster loss of activation-related antigens and accumulation of regulatory T cells.
Decreased proliferation of CD4(+) lymphocytes of elderly people is at least in part due to lowered proportion of cells that are capable of dividing and producing viable progeny (effective precursors). We show that age-dependent reduction in effective precursor numbers depends on the one hand, extensive, activation-dependent apoptosis occurring from the very onset of stimulation and, on the other, the accumulation of non-dividing, regulatory (suppressor) CD4(lo)CD25(+)CD28(lo) T cells. In addition, analysis of changes in surface expression of activation-related antigens, including CD25, CD69, and PCNA in consecutive generations of dividing CD4(+) cells traced by carboxyfluorescein diacetate succinimidyl ester staining showed variable patterns of these changes that may relate to various aspect of impaired division of these cells in elderly.
Bryl
Ewa
E
Department of Immunopathology, Medical University of Gdansk, Debinki 7, Gdansk 80-211, Poland. ebryl@amedec.amg.gda.pl
Witkowski
Jacek M
JM
D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008875:Middle Aged; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology
D015703:Antigens, CD; D018809:Proliferating Cell Nuclear Antigen