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Fumonisin is a group of structually related mycotoxins produced by Fusarium sp
ecies. Fumonisin B1（FB1）, the major compound of fumonisin mycotoxins, has lo
ng been implicated as an etiological agent of many fatal diseases in the anima
l, such as equine leukoencephalomalacia（ELEM）and porcine pulmonary edema（PP
E）; it is also responsible for the immunotoxic effect in poultry and hepatoca
rcinogenesis in rats. The purpose of the study was to evaluate the potential e
ffect of FB1 on swine pulmonary alveolar macrophages（AM）and peripheral blood
mononuclear cells（PBMC）。The cells were exposed in vitro to 2, 10, and 20 m
g FB1/ml for 6, 24, 48, and 72 hours in AM, and for 12, 24, 48, and 72 hours i
n PBMC. The cell viability and various functions of both cells were examined a
fter FB1 exposure. In addition, AM and PBMC were also activated by LPS and Con
A, respectively, to compare the susceptibility of resting and activated cells
to FB1 toxicity. For AM, parameters examinedincluded cell viability; phagocyto
tic and microbicidal potential; free radical（Superoxide and hydrogen peroxide
）（O2- and H2O2）, TNF-a, and PGE2 production. For PBMC, cell viability; IL-2
production; DNA, RNA, and protein synthesis were examined. For AM, the result
s showed that following FB1 exposure, 1）the cell viability was elevated withi
n the first incubation day, but was decreased thereafter. The trend of cell re
sponse appeared earlier in LPS-stimulated (activated) than in resting AM; 2）T
PA-stimulated free radical production, including O2- and H2O2 ,was inhibited w
ith a significant reduction in O2- and H2O2 production after 48 and 72 hours o
f treatment, respectively, in both LPS-stimulated (activated) and resting AM;
3）the phagocytotic potential was depressed significantly after 48 hours of in
cubaton in both LPS-stimulated (activated) and resting AM with the former affe
cted more evidently; 4）microbicidal potential was reduced significantly by 72
hours in both LPS-stimulated (activated) and resting AM in a dose-dependent m
anner; 5）TNF-a production in LPS-stimulated (activated) AM was decreased thro
ugout the study while in resting AM it was reduced during the early time point
s but increased after 48 hours; 6）changes in PGE2 production were different i
n LPS-stimulated (activated) and resting AM. It was increased in activated AM
while in resting AM, it was increased before 24 hours of incubation followed b
y decreasing later on. As for the effect of FB1 on PBMC, it is revealed that 1
）the cell viability was declined throughout the study; 2）IL-2 production was
only slightly reduced; 3）the DNA, RNA, and protein synthesis were all decrea
sed with RNA and protein synthesis affected the most. Significant inhibition i
n RNA synthesis occurred 6 hours after FB1 exposure. The inhibitory effect of
FB1 on RNA and protein synthesis was more obvious in ConA-stimulated PBMC than
in resting cells, but there was no difference between the two types of PBMC i
n DNA synthesis. The results suggest that FB1 mycotoxicosis has the potential
to cause immunosuppression in swine. Thus, long-term ingestion of FB1-contamin
ated feed may result in an increased disease susceptibility in pigs.
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