Inhibition of chlamydia trachomatis growth by human interferon-α: Mechanisms and synergistic effect with interferon-γ and tumor necrosis factor-α

Abstract

We have evaluated the effect of natural human interferon (IFN)-α on the growth of chlamydia trachomatis in human epithelial cells in vitro and revealed that IFN-α has reduced both growth and infectivity of C. trachomatis. The effect of IFN-α was reversed by the addition of exogenous L-tryptophan and iron to the culture medium, suggesting that antichlamydial effect of IFN-α was caused by depletion of intracellular tryptophan and iron, both of which are essential for chlamydial growth. When IFN-α was combined with another antichlamydial cytokines, IFN-γ and tumor necrosis factor (TNF)-α, the effect was synergistically enhanced. Therefore, IFN-α would act coordinately with other cytokines such as IFN-γ and TNF-α, and play an important role in host defense against infection and in the establishment of persistent chlamydial infection of host, in which the organism remains viable, but in a culture-negative state. Copyright © 2005 Biomedical Research Press.