SUMMARY: Influenza viruses require a proteolytic enzyme (an enzyme that can cut or cleave proteins), like trypsin, in order to activate a surface protein that allows them to attach/infect our cells. Since viruses can only replicate inside cells, having this proteolytic enzyme is crucial; without it, the virus can’t make you sick. This study reconstructed the 1918 influenza virus by making a virus with 8 of the known viral genes. The study showed that the 1918 influenza virus was able to replicate both with and without trypsin. Vaccines made from the attachment surface proteins (hemagglutinin) were effective.
LESSON COMMENTS: This paper can be tied to enzyme function, specifically the cleaving of pepsinogen to pepsin in the stomach. For more advanced high school classes, one can also talk about viral lytic cycles and how vaccines target specific proteins/PAMPs on pathogens.
For middle school and less advanced students, this is a good way to introduce the concept of protein specificity, vaccines, mutations, and stresses that drive evolution.
For all levels, this would be a good article to talk about scientific method, specifically sample sizes.
Snydman, D. (2006). Characterization of the Reconstructed 1918 Spanish Influenza Pandemic Virus. Yearbook of Medicine, 2006, 68-69.