Effects of human recombinant interleukin 5 and 3 on the differentiation of cord blood-derived eosinophils and basophils.

When mononuclear cells from umbilical-cord blood were cultured for 3 weeks, low concentrations of interleukin 3 supported the preferential growth of basophils, with eosinophils comprising a smaller proportion. These basophils contained 0.15-0.3 microgram histamine per 10(6) cells, and released histamine by the IgE-dependent and -independent stimuli. Interleukin 5 increased the number and proportion of eosinophils in a dose-dependent manner without affecting the proliferation of other cell types in the interleukin 3-supplemented cultures. These cultured eosinophils could be activated by platelet-activating factor.