Virus engineered to rely on artificial amino acids, used as vaccine

Synthetic biology has become a catch-all term for attempts to engineer organisms to do things they normally wouldn’t. Efforts so far have ranged from assembling logic circuits inside bacteria to replacing an entire bacterial genome with one synthesized from scratch. So far, however, the field has largely produced some extremely impressive proofs-of-concept. There haven’t been a lot of advances with obvious practical uses. That may be about to change. Researchers have taken a technique that’s been used a number of times before—engineering cells to use an artificial amino acid—and applied it to make a flu virus that acts as a vaccine. The vaccine is highly effective and, because it depends on an amino acid our cells don’t use, it can’t cause infections in us. Best yet, if the vaccine gets into cells with a normal flu virus, it interferes with its ability to generate an infection. All of our proteins are made...