Interleukin-4 gene expression in high and low IgE responder mice.

Interleukin-4 (IL-4) gene expression in murine spleen cells was examined by stimulation with concanavalin A (Con A). Spleen cells from a DBA/2 strain of mice, a high IgE responder, expressed IL-4 mRNA within 3 h after incubation with Con A. Maximal IL-4 mRNA expression was observed 6-9 h after stimulation. The amount of IL-4 mRNA induced by Con A was greatest in spleen cells obtained from high IgE responder strains of mice. A trace amount of mRNA was induced in spleen cells from low IgE responder (SJL) mice. The amount of mRNA induced in spleen cells from an intermediate IgE responder (C57BL/6) was smaller than that from high responders, but significantly greater than that from low responders. Spleen cells from IgE nonresponders (SJA/9) developed only a negligible amount of IL-4 mRNA after stimulation with Con A. Time course and optimal concentration of Con A for the expression of IL-4 mRNA were essentially the same in high (DBA/2) and low (SJL) responder strains of mice. The decreased expression of IL-4 mRNA in low IgE responder spleen cells upon stimulation was not due to the decrease in Thy-1-positive cells or L3T4-positive cells in the spleen. The results obtained in the present study may indicate that high and low IgE responder traits are determined depending on their levels of IL-4 mRNA expression.