Scanning electron micrograph of human cells infected with influenza virus

A human cell (orange) infected with influenza virus (pink), which can be thwarted by a molecule that resembles a flu-fighting antibody. Credit: Steve Gschmeissner/SPL

Vaccines

A little molecule that can disarm a lethal dose of flu virus

Drug candidate imitates a naturally occurring immune protein that binds to influenza virus.

A molecule that mimics an antiviral antibody protects mice from ordinarily lethal doses of influenza.

The flu virus causes hundreds of thousands of deaths every year — and many more when a major new variant emerges. The viral proteins that vaccines and drugs are designed to target mutate continually, making therapies difficult to develop.

Maria van Dongen at Janssen Pharmaceutical Companies of Johnson & Johnson in Leiden, the Netherlands, Ian Wilson at the Scripps Research Institute in La Jolla, California, and their colleagues engineered a small molecule that mimics the action of a natural antibody that is active against a broad spectrum of flu strains. Like the antibody, the molecule, JNJ4796, binds to an infrequently mutated region of a flu surface protein. When mice were given the molecule, it protected 100% of the animals against an otherwise lethal dose of the H1N1 flu strain.

Small molecules are easier to make than antibodies and can be administered as a pill, whereas antibodies are injected.