Effect of interleukin-3, interleukin-5 and hyaluronic acid on cultured eosinophils derived from human umbilical cord blood mononuclear cells

Background: Several studies have shown that cultured eosinophils can be gen erated from human umbilical cord blood mononuclear cells (UCMC) in the pres ence of interleukin (IL)-3 and IL-5 in vitro. Other reports have indicated that cellular adhesion to hyaluronic acid (HA) enhances the proliferation o f cultured eosinophils derived from CD34+ cells purified from UCMC. The aim of this study was to obtain large numbers of mature eosinophils from UCMC using IL-3, IL-5 and HA, and to investigate their functions; Methods: We ex amined several combinations of IL-3 and IL-5 and their effect on eosinophil development from UCMC in HA-coated on non-coated flasks. We also examined whether cultured eosinophils degranulated eosinophil-derived neurotoxin (ED N) induced by secretory immunoglobulin A conjugated to sepharose beads (slg A-beads) and responded to eotaxin. Results: Culture with HA-coated flasks f ar 35 days tin the presence of IL-3 and IL-5, with IL-3 omitted after day 1 4 of culture) caused a 11.2-fold augmentation in the proliferation of UCMC. On day 35 of the culture, 98% of cultured cells were eosinophils judging f rom May-Grunwald and Giemsa staining and transmission electron micrographs. The EDN content of the cultured eosinophils on day 35 was 156 ng/10(5) cel ls. Cultured eosinophils degranulated EDN induced by slgA-beads and respond ed to eotaxin by chemotaxis and intracellular Ca2+ mobilization. Conclusion : We found a useful culture system to obtain large numbers of eosinophils d erived from UCMC, which may facilitate the investigation of eosinophil func tion, since there was no significant difference in response to slgA-beads a nd eotaxin between cultured and peripheral eosinophils.