Relative NO produced in haemocytes from schistosome-susceptible (A) and schistosome-resistant (B) B. glabrata strains challenged with different concentrations of ESPs (0, 0.1, 1, 10 and 20 μg/ml) over time. Equal numbers of haemocytes (3 × 103 cells per well) from each snail strain were used in each experiment. Mean relative fluorescence from a single pool of haemolymph (± SEM, n = 3) is shown for each time point as a proportion of background fluorescence (no DAF-FM diacetate, indicated by the dotted line). Data shown are from one assay and are representative of three different assays conducted on separate days. *P ≤ 0.05 for differences in mean fluorescence values at 2 h between unexposed haemocytes and haemocytes exposed to ESPs.