Effects of smokeless tobacco and nicotine on cytokine responses of murine memory T cells

Smokeless tobacco (ST) is associated with oral cancer and periodontal disease. These effects are partially due to ST and nicotine's influence on naive T cell cytokine responses. It is unclear if the effect of ST or nicotine could be seen during secondary stimulation of memory T cells. To determine the influence of ST on memory T cells, splenic mononuclear cells (SPM) were exposed to 1:102 to 1:103 dilutions of ST, 10-100 ug/ml nicotine, or medium during 4 days of stimulation with anti-CD3. SPM were then washed extensively and restimulated with anti-CD3 plus anti-CD28 without ST or nicotine. Production and expression of IL-2, IL-4, IL-10 and IFN-g were evaluated using ELISA and RT-PCR. T cells exposed to 10 ug/ml nicotine during primary stimulation produced 2-fold more IFN-g during secondary responses compared with controls. Sustained IL-10 gene expression was noted even 4 days after primary stimulation in the presence of nicotine, which resulted in 30% more IL-10 accumulation during secondary stimulation compared with controls. Exposure to ST during the primary T cell response led to significantly higher production of IL-2 (+270%), IL-4 (+69%), IFN-g (+300%), and IL-10 (+73%) during secondary responses without ST. These results indicate that exposure to ST or nicotine during the primary immune response will significantly influence cytokine production during the response of memory T cells.