Many vaccines, including those for influenza, polio, and measles, consist of a killed or disabled version of a virus. However, for certain diseases, this type of vaccine is ineffective, or just too risky. An alternative, safer approach is a vaccine made of small fragments of proteins produced by a disease-causing virus or bacterium. This has worked for some diseases, but in many cases these vaccines don’t provoke a strong enough response. Now a team of engineers from the Irvine Lab has developed a new way to deliver such vaccines directly to the lymph nodes, where huge populations of immune cells reside: These vaccines hitch a ride to the lymph nodes by latching on to the protein albumin, found in the bloodstream. In tests with mice, such vaccines produced very strong immune responses.