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 generated from human umbilical cord blood mononuclear cells (UCMC) in the presence of interleukin (IL)-3 and IL-5 in vitro. Other reports have indicated that cellular adhesion to hyaluronic acid (HA) enhances the proliferation of 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 examined 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 (EDN) induced by secretory immunoglobulin A conjugated to sepharose beads (sIgA-beads) and responded to eotaxin.

RESULTS

Culture with HA-coated flasks for 35 days (in the presence of IL-3 and IL-5, with IL-3 omitted after day 14 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 from May-Grünwald and Giemsa staining and transmission electron micrographs. The EDN content of the cultured eosinophils on day 35 was 156 ng/105 cells. Cultured eosinophils degranulated EDN induced by sIgA-beads and responded to eotaxin by chemotaxis and intracellular Ca2+ mobilization.

CONCLUSION

We found a useful culture system to obtain large numbers of eosinophils derived from UCMC, which may facilitate the investigation of eosinophil function, since there was no significant difference in response to sIgA-beads and eotaxin between cultured and peripheral eosinophils.