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Clinical and Diagnostic Laboratory Immunology, Sep 1996, 578-583, Vol 3, No. 5
RL Gregory and LE Gfell
Previously, we reported that secretory component (SC), lactoferrin (LF),
and lysozyme (LY) levels were significantly lower in saliva from smokeless
tobacco (ST) users than in saliva from control non-tobacco users. However,
the levels of salivary immunoglobulin A were significantly higher, albeit
with an altered attachment of SC, in ST users than in control subjects. SC,
LF, and LY are synthesized by secretory epithelial cells at mucosal sites
adjacent to lymphocyte regions. In the present report, HT-29 human
epithelial cells, cultured with various concentrations of an ST aqueous
extract or pure nicotine (0 to 1 mg/ml) or cotinine (0 to 5 mg/ml),
exhibited significantly lower levels of cell-associated cell lysate (CL)
and secreted culture supernatant (CS) SC, LF, and LY than cells cultured
without ST components. Nicotine significantly decreased (P < or = 0.05)
the synthesis of SC by 20 to 100%, LF by 20 to 60%, and LY by 5 to 75% of
CL and CS control values. Studies also indicated significant decreases (P
< or = 0.05) in SC, LF, and LY levels in both CL and CS of cells
cultured with ST aqueous extract or cotinine. Total cell numbers and
metabolic activity significantly decreased primarily when cells were
incubated with higher concentrations of ST extract, nicotine, or cotinine.
The addition of human recombinant interleukin-4 or gamma interferon
diminished the effects ST had on HT-29 cell synthesis of SC, LF, and LY.
Our data indicate that nicotine, cotinine, and ST have an adverse effect on
synthesis and secretion of SC, LF, and LY. These effects were below ST
concentrations found to be cytotoxic for secretory epithelial cells.
Furthermore, addition of interleukin-4 or gamma interferon reduced the
suppressive effect of ST on synthesis or secretion of SC, LF, or LY.
Copyright © 1996 by the American Society for Microbiology. All rights reserved.
Effect of nicotine on secretory component synthesis by secretory epithelial cells
Department of Oral Biology, Indiana University, Indianapolis 46202- 5186, USA. RGREGORY@IUSD.IUPUI.EDU
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