Why should cell biologists study microbial pathogens?

Welch, Matthew D.

is a Federal Drug Administration (FDA)-approved drug that is used in combination therapy to treat HIV infection. It inhibits viral entry into cells by binding to the chemokine-and HIV-receptor CCR5 (Wood and Armour, 2005) . Other inhibitors of host proteins involved in HIV infection are also in development (Arhel and Kirchhoff, 2010) . Moreover, inhibitors of the cellular receptors for other viruses have been identified. A small molecule that inhibits cellular infection with Ebola virus, the causative agent of a dramatic hemorrhagic fever, works by binding to the endosomal protein NPC1 (Côté et al., 2011) . In fact, the identification of this inhibitor revealed that NPC1 is a crucial factor for Ebola virus infection. A more recent study identified an engineered protein that inhibits infection with the influenza virus, which causes flu, by binding to sialic acid, which is used as a receptor for virus entry (Connaris et al., 2014) . One intranasal dose of this inhibitor protected mice from an otherwise lethal dose of the 2009 pandemic H1N1 virus, while also enabling sufficient viral replication to potentially protect the animals from future infection.