Neutralizing antibodies were thought to be essential to helping the body fight off viruses, but it turns out that this is not always the case.

Antibodies are made by immune cells called B cells. A team led by Matteo Iannacone and Ulrich von Andrian at Harvard Medical School in Boston, Massachusetts, studied mice engineered to make their B cells incapable of producing antibodies but still able to make a chemical called lymphotoxin α1β2. When the animals were infected with vesicular stomatitis virus, this lymphotoxin caused another type of immune cell, the macrophage, to be preferentially infected by the virus. Infected macrophages secreted another molecule, type I interferon, which prevented fatal viral infection of the nervous system.

The findings suggest that innate immunity — the immune system's first line of defence, which includes macrophages — has an unappreciated role in combating viral infections.

Immunity http://dx.doi.org/10.1016/j.immuni.2012.01.013(2012)