Defective expression of high affinity IL-2 receptors on activated T cells from aged humans.
The proliferative response of T cells from aged humans to a number of mitogens is significantly reduced. We report here that there is a decrease in high affinity IL-2 receptor (IL-2R) expression on activated T cells from aged humans. Scatchard analysis of the binding of [125I]IL-2 demonstrates fewer high affinity IL-2 binding sites. Autoradiographic techniques demonstrate that this results from there being fewer activated T cells from old as compared to young donors that express high affinity IL-2R. However, T cells from old donors that do not express high affinity IL-2 binding sites express both the IL-2 binding 55 and 75 kd chains. Thus, although the two IL-2 binding peptides are expressed on activated T cells from old donors, expression of the high affinity IL-2R is reduced. This may explain the decreased ability of T cells from old donors to respond to IL-2. The impaired ability of activated T cells from old donors to express high affinity IL-2R while expressing the 55 and 75 kd chains may provide insights into the mechanisms of IL-2 interactions with its receptor.
Schwab
R
R
Department of Medicine, Cornell University Medical College, New York, NY 10021.
Pfeffer
L M
LM
Szabo
P
P
Gamble
D
D
Schnurr
C M
CM
Weksler
M E
ME
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D008875:Middle Aged; D008934:Mitogens / Q000494:pharmacology; D015375:Receptors, Interleukin-2 / Q000172:deficiency* / Q000378:metabolism; D013601:T-Lymphocytes / Q000737:chemistry*
D007376:Interleukin-2; D008934:Mitogens; D015375:Receptors, Interleukin-2