Modulation of dab (Limanda limanda, L.) macrophage respiratory burst activity

Dab Limanda limanda kidney macrophages were isolated by adherance to tissue culture plates and their respiratory burst activity subsequently analysed. Several seeding cell concentrations were tested, with 10⁷ and 2 × 10⁷ cells ml^-1 giving significant respiratory burst activity. Respiratory burst activity of the isolated macrophages was also investigated following a pre-incubation for 24h or 48h with a variety of concentrations of human recombinant tumor necrosis factor a (rTNFa), β-glucan, Concanavalin-A (Con-A) or lipopolysaccharide (LPS). All four stimulants were able to up-regulate dab macrophage respiratory burst activity at particular concentrations, especially after a 48 h incubation when 6·25 and 12·5 iu ml^-1 rTNFa, 0·125, 0·25 and 0·5 μg ml^-1 β-glucan, 1·25 and 2·5 μg ml^-1 Con-A and 3·125, 6·25, 12·5, 25 and 50 μg ml^-1 LPS induced significant increases. LPS and Con-A gave the largest relative increases in activity. However, the highest concentrations tested (50 and 100 iu ml^-1 rTNFa, 2, 4 and 8 μg ml^-1 β-glucan, 80 μg ml^-1 Con-A and 200 μg ml^-1 LPS) were inhibitory. The data are discussed in relation to the mode of action of each compound and the usefulness of such assays in pollution monitoring.