IMMUNOTOXIC EFFECTS OF SMOKELESS TOBACCO ON THE ACCESSORY CELL-FUNCTION OF RAT ORAL EPITHELIUM

Smokeless tobacco (ST) is known to adversely effect the oral mucosa, b ut knowledge about the influence on immune defence is limited. Few stu dies have investigated the effect of ST on the local immune response. In the present study, we have assessed the effect of a crude Swedish m oist snuff (SS) extract, alkaloids, and nitrosamines on T-cell mitogen ic response to Con A using epithelial cells, including Langerhans cell s, of the rat oral mucosa as accessory cells. SS extract at a concentr ation of 4% reduced the T-cell proliferation by 50% (IC50 = 4%). Pretr eatment of either oral epithelial cells or T-cells with SS extract als o gave a significant inhibition of T-cell proliferation. This effect w as not obtained following preincubation with SS components as alkaloid s and different tobacco-specific nitrosamines (TSNA). None of the test ed compounds were found to possess any mitogenic properties. This in v itro study showed that SS extract can evoke an immunosuppressive effec t on mitogen-driven T-cell proliferation using cells from oral epithel ium as accessory cells. This effect was more pronounced when SS extrac t was employed compared to when the single SS components were used alo ne.