Potentiation of IL-2-induced t-cell proliferation by retinoids.
We evaluated the capacity of retinoids to potentiate proliferative responses of murine T-cells to recombinant human interleukin 2 (rIL-2). Concanavalin A (Con A) prestimulated spleen cells responded in a dose-dependent manner to added rIL-2. All-trans-retinoic acid (RA) at 10(-8) M potentiated the proliferative response by fivefold at saturating levels of IL-2. In similar experiments, two closely related retinamides, all-trans-(phenyl)retinamide (PR) and N-(4-hydroxyphenyl)retinamide (4-HPR), also potentiated murine splenocyte rIL-2 responses. Potentiation of IL-2-induced proliferation was dose-responsive to the concentration of added retinoid with peak potentiation occurring at 10(-10) - 10(-8) M in the presence of 10 U/ml rIL-2. Significant potentiation was observed at retinoid concentrations as low as 10(-14) M. Fluorescence flow cytometry of the responding cells revealed that among L3T4+, Lyt-2+ or total T-cells, at 72 h following Con A stimulation, essentially all of the cells expressed IL-2 receptors (IL-2R). This apparently represents near maximum IL-2R expression and treatment of the cells with retinoids did not increase IL-2R expression at that time point. The potentiation of IL-2 responses by retinoids was also observed with IL-2-dependent HT-2 cells, 98% of which were IL-2R positive. HT-2 proliferative responses to rIL-2 were potentiated as much as fourfold by 10(-10) M RA. HT-2 proliferative responses to rIL-2 were potentiated by all three retinoids dose dependently. Significant potentiation was observed with as little as 10(-14) M retinoid. Retinoids in the absence of IL-2 induced no proliferative responses. These data suggest that retinoids can augment the capacity of IL-2 to induce T-cell proliferation using Con A-activated murine splenic T-cell blasts and a long-term-cultured T-cell line.
Jiang
X L
XL
Birmingham Veterans Administration Medical Center, AL.
Dillehay
D L
DL
Everson
M P
MP
Tilden
A B
AB
Lamon
E W
EW
D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D005260:Female; D007376:Interleukin-2 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D015375:Receptors, Interleukin-2 / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D014212:Tretinoin / Q000494:pharmacology*
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D015847:Interleukin-4; D014212:Tretinoin