Vaccines are unarguably one of the greatest success stories in medical history, eliminating or largely curtailing numerous age-old scourges such as smallpox and polio. But researchers' track record in coming up with effective vaccines for today's major and emerging diseases is, by and large, dismal. A Yale University spinoff, Vaxinnate, hopes to use recent breakthroughs in basic immunology to re-invigorate vaccine development and create new vaccines for cancer, West Nile virus, and influenza.

In the last decade, immunologists have uncovered the biological mechanisms of a very different kind of immune reaction than the "adaptive" response they've long studied. This "innate" immune response kicks in within mere minutes of an infection. In contrast, the adaptive response, with its familiar antibodies, takes days to get up to fighting speed. An effective vaccine should elicit both types of responses, and researchers now understand that the vaccines of old -- made with weakened live viruses -- did just that. But to avoid the risks inherent in using live viruses, vaccine developers have turned to individual proteins as immune-system stimulators. Although they're safer and can generally boost antibody production, these vaccines often fail to prod the innate immune system to action.