Biased Vaccine

Manipulating the sites of synonymous mutations has allowed scientists to design genes that speed up protein manufacture, but the same technique can also be used to slow it down. Steffen Mueller and his colleagues at Stony Brook University recently took this approach to design a safer polio vaccine. Live viruses make the most potent vaccines because they provoke a strong immune response in the recipient, but live vaccines can reproduce and mutate, potentially causing disease. Mueller’s group took advantage of microbes’ preference for using certain codons to maximize the efficiency of protein production by designing a poliovirus that substituted rarer, less efficient codons in sequences encoding the viral shell. The resulting virus was able to copy itself, albeit more slowly. After the investigators administered the engineered virus to mice, the animals were protected from infection when they were later exposed to wild poliovirus. This technique for taking advantage of codon bias to create a live but weakened vaccine could be applied to other pathogens as well to produce potent but safer vaccines.