[Protein phosphorylation in interleukin-5 (IL-5)-stimulated human peripheral blood eosinophils]

Peripheral blood eosinophils from normal healthy subjects were purified on a Percoll gradient and were incubated with H3(32)PO4. 32P-labeled eosinophils were stimulated by IL-5 under various conditions. After the reaction was stopped. SDS/PAGE and autoradiography were performed to determine the incorporation of 32P into proteins. 32P incorporation into the bands with molecular weights of 52 kDa and 65 kDa was obtained. 32P incorporation into the band of 52 kDa was presumed to be non-specific. 32P incorporation into the band of 65 kDa increased when it was incubated with 1-3 U/ml IL-5. IL-5-induced 32P incorporation into the band of 65 kDa was dependent on the temperature of the reaction system and the incubation time with IL-5. However, IL-5-stimulated eosinophils generated no significant superoxide anion as measured by MCLA-dependent chemiluminescence method.