摘要：

Recent investigations indicate that dietary exposure to the trichothecene vomitoxin increases total and antigen-specific serum immunoglobulin A (IgA) and glomerular IgA accumulation in mice. In this study, the effects of 25 ppm dietary vomitoxin on the histological and lymphocytic profile of component immune organs in the mucosal lymphocyte migratory pathway were evaluated in the B6C3F 1 mouse. Vomitoxin administration resulted in marked stimulation of the size and frequency of germinal centres in Peyer's patches, mesenteric lymph nodes and the spleen. A slight increase in the percentage of B cells in the Peyer's patch was observed, although vomitoxin treatment had no effect on the percentage of B cells in the spleen. The percentage of IgA + cells in Peyer's patches and spleen were approximately twice that of controls at 4, 8 and 12 wk of vomitoxin exposure whereas the percentage of IgG + cells decreased in these two organs. Exposure to vomitoxin increased the percentage of T cells in Peyer's patches and the spleen. The percentage of CD4 + cells (T helper subset) increased slightly in Peyer's patches and more markedly (30–50%) in the spleen following vomitoxin treatment. Contrastingly, there was only a slight increase in the percentage of CD8 + cells (T cytotoxic/suppressor subset) in the spleens of vomitoxin-treated mice in comparison with controls, and no effect in Peyer's patches. The relative effects of vomitoxin on these two T cell populations was also reflected in increased CD4 +:CD8 + ratios in Peyer's patches and spleen. These results are consistent with the hypothesis that dietary vomitoxin modulates normal regulation of the IgA response at the Peyer's patch level and that this is manifested in an altered lymphocyte distribution pattern in both the mucosal and systemic compartment. Notably increased levels of IgA + and CD4 + cells are indicative of IgA-producing progenitors and T helper subsets, respectively, that in tandem could favour IgA hyperproduction and elevated IgA in serum.

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