Effect of patulin on microbicidal activity of mouse peritoneal macrophages.

Patulin, a fungal metabolite shown previously to exert immunosuppressive effects on the cellular and humoral immune systems, was examined for its in vitro effects on some functions of murine peritoneal macrophages. The cells were pre-incubated for 2 hr with mycotoxin concentrations of 0.01-2 micrograms/ml. Phagocytosis and phagosome-lysosome fusion were diminished above 0.1 microgram patulin/ml and lysosomal enzymes and microbicidal activity above 0.5 microgram/ml, whereas O2- production was inhibited only above 2 micrograms/ml. This indicated that the killing mechanism did not depend on products of the oxidative burst. The concentrations used did not decrease the cell viability. Under natural circumstances, patulin may constitute a health risk for animals.