Figure 2.

The long-term preincubation effect of IL-6 on IL-5 secretion is dependent on IL-2 availability. (a) Effects of preincubation with IL-6 on IL-5 production in freshly isolated T lymphocytes during 5 min or 24 hr in the absence and presence of neutralizing antibodies to IL-2. After preincubation with or without IL-6, T cells were stimulated with α-CD3/α-CD28 during 8 hr. IL-5 protein levels are expressed as percentage (x ± SEM, n = 8) of the production after stimulation in the absence of IL-6 and α-IL-2. (b) Effects of preincubation with IL-6 on IL-4 production in freshly isolated T lymphocytes during 5 min in the absence and presence of neutralizing antibodies to IL-2. After preincubation with or without IL-6, T cells were stimulated with α-CD3/α-CD28 during 8 hr. IL-4 protein levels are expressed as percentage (x ± SEM, n = 5) of the production after stimulation in absence of IL-6 and α-IL-2. (c) Effect of IL-6 preincubation during 24 h on IL-5 production in T lymphocytes, in the presence of increasing IL-2 concentrations (0, 2, 10, 100 ng). After preincubation with IL-6, T cells were stimulated with α-CD3/α-CD28 during 8 hr. IL-5 protein levels are expressed as a percentage (x ± SEM, n = 4) of the production after stimulation with α-CD3/α-CD28 alone. *, P < 0·05 between values of relative IL-5 protein in presence and in absence of IL-6.