Age-related changes of expression of IL-2 receptor subunits and kinetics of IL-2 internalization in T cells after mitogenic stimulation.
The age-associated changes of the expression of IL-2 binding molecules p55/Tac(alpha chain) and p70/75(beta chain) were examined after phytohemagglutinin (PHA) stimulation. The expressions of both p55/Tac molecules and p70/75 molecules were significantly reduced in the aged compared with those in the young persons. The amounts of p55/Tac and p70/75 molecules on T cells from the aged were 55% and 59% of those on young ones, respectively. The ratio of the amount of p70/75 to that of p55/Tac in aged T cells was 0.28 and that in young ones was 0.26. The ratio was somewhat higher in the aged but not significantly. We also examined the kinetics of IL-2 internalization mediated by its receptor. The calculated t1/2 of receptor-mediated IL-2 internalization was 17 min in the aged and 16 min in the young, respectively. There was no kinetic difference between the 2 groups. The percentage of the internalized IL-2 to the sum total was 58.2% in the aged and 73.4% in the young (P less than 0.02). the amount of internalized IL-2 in T cells from the aged was 48.6% of that from the young (P less than 0.01).
Hara
H
H
Third Department of Internal Medicine, Osaka University Hospital, Japan.
Tanaka
T
T
Negoro
S
S
Deguchi
Y
Y
Nishio
S
S
Saiki
O
O
Kishimoto
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism*; D007700:Kinetics; D008213:Lymphocyte Activation; D010446:Peptide Fragments / Q000378:metabolism; D010835:Phytohemagglutinins / Q000494:pharmacology; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*
D007376:Interleukin-2; D010446:Peptide Fragments; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2