ROLE OF MESSENGER-RNA STABILITY IN THE DIFFERENT PATTERNS OF CYTOKINEPRODUCTION BY CD4(+) CELLS FROM YOUNG AND OLD MICE

CD4(+) cells from young (3 months) and old (19 months) mice were stimu lated by plate-bound anti-CD3 monoclonal antibody (mAb) alone or also by soluble anti-CD28 mAb. Supernatants were analysed by enzyme-linked immunosorbent assay (ELISA) to determine cytokine concentrations. Tota l RNA was extracted from cells, reverse transcribed and the cDNA ampli fied by polymerase chain reaction (PCR) to evaluate the amount of spec ific mRNA. The results indicate that anti-CD3 alone is not sufficient to induce interleukin-2 (IL-2) production in CD4(+) cells from both yo ung and old mice. However, anti-CD28, together with anti-CD3 mAb, indu ces a much higher production of IL-2 in CD4(+) cells from young as com pared with old mice. Conversely, interferon-gamma (IFN-gamma) producti on is also induced by anti-CD3 alone and is higher in CD4(+) cells fro m old as compared with young mice. Upon addition of anti-CD28 mAb, IFN -gamma production increases in both groups, but it remains much higher in old than in young mice. Also the production of IL-4 and IL-10 is i nduced by anti-CD3 mAb but it is increased by the addition of anti-CD2 8 mAb. CD4(+) cells from old mice produce more IL-4 and IL-10 as compa red with cells from young mice. The amounts of cytokine specific mRNA in CD4(+) cells from young and old mice parallel the cytokine levels i n culture supernatants. Results on the mRNA turnover indicate that whe n CD4(+) cells are stimulated by anti-CD3 or costimulated also by anti -CD28 mAb, the IFN-gamma, IL-4 and IL-10 specific mRNAs are more stabl e in old than in young mice, suggesting that mRNA stability has a rele vant role in the different patterns of cytokine production.