Previous clinical studies have shown a correlation between smoking and several diseases. Previous studies have demonstrated the effects of both whole tobacco smoke as well as selected components on PMN functions. In this study, the effects of nicotine, cotinine, and ammonium chloride were observed in vitro for PMN phagocytic function and Fcy receptor or C3bi receptor expression. Human peripheral PMNs were collected from healthy nonsmokers and incubated with nicotine (1×10-2 M to 10-6M), cotinine (1×10-2M to 10-6M) or ammonium chloride (1×10-2M to 10-6 M) for 45 minutes at 37°C.
For analysis of PMN phagocytosis, PMNs were incubated with fresh human serum, RPMI 1640 media, and fluoresbrite beads for 30 minutes. The patterns of the ingestion beads by PMNs were estimated by flow cytometer on 5000 cells/sample. For Fcγ receptor staining, PMNs were incubated with FITC conjugated mouse anti-Fcγ receptor monoclonal antibody (OK-NK) . For C3bi receptor staining, PMNs were first incubated with mouse anti-human monocyte/granulocyte monoclonal antibody (OKM1), and then incubated with FITC conjugated goat anti-mouse IgG. Fcy and C3bi staining values were estimated by flow cytometer. Statistical significant depressions of % phagocytosis were observed in 1×10-2 M of nicotine and cotinine groups (p<0.05: unpaired t test) . Depression tendencies of average number of ingested beads per cell were observed in all groups (N. S.) . Statistical significant depressions of Fcy and C3bi receptor staining values were observed in 1×10-2M and 1× 10-4M of nicotine, cotinine, and ammonium chloride groups, and 1×10-6M of cotinine groups (p<0.01 or p<0.05: unpaired t test) . These studies demonstrated that nicotine, cotinine, and ammonium chloride inhibit PMN Fcγ and C3bi receptor expression which may impair PMN functions such as phagocytosis.
