Interferon-induced inhibition of Chlamydia trachomatis: dissociation from antiviral and antiproliferative effects.

The yield of infectious Chlamydia trachomatis was analyzed in human (HeLa) and mouse (McCoy) cell lines treated with the human interferon (IFN) subtypes IFN-alpha A and IFN-alpha D, with their hybrids [IFN-alpha AD (BglII), IFN-alpha AD (PvuII), and IFN-alpha DA (BglII)] constructed in vitro from their expression plasmids, or with IFN-beta 1 or buffy coat IFN. In HeLa cells, a significant inhibition of Chlamydia infectivity was obtained with IFN-alpha D, IFN-alpha DA (BglII), and buffy coat IFN. In McCoy cells, IFN-alpha AD (BglII) and IFN-alpha AD (PvuII) induced a strong degree of inhibition of Chlamydia infectivity. In McCoy cells, there was a correlation among the antichlamydial, antiviral, and antiproliferative activities of the different IFNs tested. In HeLa cells, however, the ability of a particular IFN subtype to inhibit Chlamydia infectivity did not always correlate with its inhibitory effects on encephalomyocarditis virus replication or with its antiproliferative activity.