Phytohemagglutinin induced proliferation by aged lymphocytes: reduced expression of high affinity interleukin-2 receptors and interleukin-2 secretion.
Human lymphocytes from elderly and young donors were cultured with phytohemagglutinin. Cultures from two groups of aged donors, recruited respectively from our ambulatory clinic and a nursing home, incorporated less tritiated thymidine (3H-TdR) and secreted less interleukin-2 than did young donors. Furthermore, as determined for the first time by a radioligand binding receptor assay, the aged lymphoblasts possessed significantly fewer high affinity IL-2 receptors per cell. Despite a decrease in the number of high affinity receptor cells the dissociation constant (Kd) was comparable for the three groups. It was also shown that the amounts of soluble IL-2 receptors that were released into the supernatants by mitogen stimulated cells did not differ for the aged and young donors. These data suggest that defects in IL-2 production and high affinity IL-2 receptor generation may both be responsible for immune deficiency in the elderly.
Froelich
C J
CJ
Section of Rheumatology, University of Illinois College of Medicine, Chicago 60612.
Burkett
J S
JS
Guiffaut
S
S
Kingsland
R
R
Brauner
D
D
D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D002478:Cells, Cultured; D004261:DNA Replication; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000378:metabolism; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis*
D007376:Interleukin-2; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2