It isn't often that an entire field of medical science gets turned on its head. But it is becoming clear that immunology is undergoing a big rethink thanks to the discovery that antibodies, which combat viruses, work not just outside cells but inside them as well. The star of this new view is a protein molecule called TRIM21.

Until recently, the conventional wisdom was that the body fights off infection in two separate ways. First is the adaptive immune system, which works outside the cell. It generates antibodies to intercept specific invaders, locking onto them like a tracking missile and preventing them from entering the cell. A second line of defense, the innate immune system, operates within the cell; it is like an expansive air-defense network, blasting away at all invaders.

Three years ago work by Leo James, William McEwan and their colleagues at the Laboratory of Molecular Biology in Cambridge revealed that this understanding was incomplete. They found that the neutralization of adenoviruses (common viruses causing colds and other infections) by antibodies was happening mainly inside the cell, not outside, and by an unexpected mechanism.

Their announcement—a challenge to the entire field of immunology—elicited a predictable immune reaction of its own from the establishment. Sure enough, leading journals rejected the Cambridge group's paper, sometimes without even reviewing it, while key funding agencies turned down the group's grant applications.