Dispersed human intestinal mast cells were used for passive sensitization experiments. Eight biopsies (9.7 +/- 1.2 mg/biopsy) of human duodenum were collected from non-atopic children (5) and adults (5). The tissue was dispersed mechanically and enzymatically to yield single cell suspensions. The method produced 2 x 10(3) mast cells per mg wet weight of tissue in a purity of 2.8%. Passive sensitization of the mast cells was performed with the patients' own plasma and plasma obtained from atopic donors. The non-atopic mast cells were able to bind the allergen-specific IgE. In addition, passive sensitization with atopic donor-plasma enhanced the cell sensitivity and cell reactivity to anti-IgE challenge, but had no effect on the cellular response to the ionophore A23187. The study shows that the enzymatic dispersion of human intestinal mast cells produces functionally intact mast cells with preserved Fc-receptors which can be passively sensitized.