Effect of anti-interferon serum of influenza virus infection in mice.

Mice were infected by an aerosol of influenza virus Type A (0.5 LD50) and subsequently treated with 4 intranasal instillations of anti-interferon antiserum over a period of 72 h. All the mice treated with antiserum died within 7 days post-infection, whilst the mice in the control groups survived. In mice that did not receive the antibody, virus titers in the lung peaked on day 3 and then decreased again. Also, interferon was detectable both in lung homogenates and serum. In mice treated with antiserum, no interferon was detectable and the virus concentrations in the lung increased until death. These results suggest that interferon produced in the respiratory tract plays an important role in the early stages of influenza virus infection.