Resveratrol Inhibits Propagation of<i>Chlamydia trachomatis</i>in McCoy Cells

Resveratrol (RESV), an antifungal compound from grapes and other plants, has a distinct ability to inhibit the <i>Chlamydia (C.) trachomatis</i> developmental cycle in McCoy cells, a classic cell line used for chlamydial research. Inoculation of <i>C. trachomatis</i> with increasing amounts of RESV (from 12.5 to 100 <i>μ</i>M) gave a dose-dependent reduction in the number of infected McCoy cells visualized by using monoclonal antibodies against chlamydial lipopolysaccharide. A similar trend has been observed with immunoassay for major outer membrane protein (MOMP). Furthermore, there was a step-wise reduction in the number of <i>C. trachomatis</i> infective progenies caused by the increasing concentrations of RESV. The ability of RESV to arrest <i>C. trachomatis</i> growth in McCoy cells was confirmed by a nucleic acid amplification protocol which revealed dose-dependent changes in mRNAs for different genes of chlamydial developmental cycle (<i>euo</i>, <i>incA</i>, and <i>omcB</i>). Although the precise nature of the antichlamydial activity of RESV is yet to be determined and evaluated in future studies, the observed effect of RESV on <i>C. trachomatis</i> infection was not related to its potential effect on attachment/entry of the pathogen into eukaryotic cells or RESV toxicity to McCoy cells. Similar inhibitory effect was shown for <i>C. pneumoniae</i> and <i>C. muridarum</i>.