Doxycycline enhances adsorption and inhibits early-stage replication of porcine reproductive and respiratory syndrome virus in vitro.

Porcine reproductive and respiratory syndrome virus (PRRSV) has an important impact on the pig industry. Doxycycline (Dox) is a second-generation tetracycline widely used for treating bacterial infections. We evaluated the antiviral effect of Dox against PRRSV infection in Marc-145 cells that were susceptible to PRRSV infection. Dox significantly reduced the PRRSV-induced cytopathic effect and effectively restrained PRRSV replication in a dose-dependent manner. The 50% effective concentration of Dox was approximately 0.25 ± 0.05 μg/ml. We also determined the stage at which Dox influenced PRRSV replication, and showed that Dox enhanced PRRSV adsorption and inhibited the early stage of PRRSV replication after viral entry into host cells. These observations demonstrate that Dox is able to restrain PRRSV infection in cultured cells. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.