AbstractWe have shown that cultured basophilic cells, derived from human cord blood cells, release histamine and high molecular weight neutrophil chemotactic activity (HMW‐NCA), in a dose‐dependent manner following calcium ionophore and anti‐IgE challenge. The HMW‐NCA detected from human cultured basophilic cells had a similar molecular weight to that of human chopped lung challenged by anti‐IgE as determined by gel filtration chromatography. These results suggest that cultured basophilic cells might be employed for research into the chemical mediators involved in immediate hyperse