Gamma interferon given 24 hours before and up to 24 hours after exposure completely protects mice from death from Ebola

A new study led by University of Iowa virologist Wendy Maury, PhD, suggests that gamma interferon, which is an FDA-approved medicine, may have potential as an antiviral therapy to prevent Ebola infection when given either before or after exposure to the virus. Ebola infection appears to be a stepwise process. First, the virus targets and infects macrophages or dendritic cells, two types of immune system cells found in the liver, spleen, and lymph nodes. Ebola then replicates in those cells. Following this initial infection, which happens at day 3 or 4 in non-human primates, Ebola virus is released into the blood and infects a plethora of other different cell populations.

Gamma interferon inhibits the virus's ability to infect human and mouse macrophages, in part by blocking virus replication in the cells. The researchers then showed that pretreating mice with interferon gamma 24 hours before exposure protects the animals from infection and death. To their surprise, the researchers found that treatment up to 24 hours after what would have been a lethal exposure also completely protected the animals from death, and the scientists could no longer detect any Ebola virus in the mouse cells. These findings suggest that interferon gamma may be useful both as a prophylaxis and post-exposure treatment against Ebola.

The team still has to determine how late gamma interferon can be given to the mice and still prevent infection. However, the results suggest a window of time after exposure when gamma interferon may be an effective antiviral therapy