Influenza, or the flu, is caused by a group of RNA viruses. These viruses contain up to 8 separate pieces of RNA encoding 11 different proteins. The reason why there is a different flu strain each year is that these individual pieces of RNA, and even sections within the pieces, can be swapped around. In other words, flu viruses have tremendous variability. Antibodies against last year’s flu probably won’t recognize this year’s flu.
Researchers at Rice University and Baylor College of Medicine (BCM) may have found a way around this problem. They studied the hemagglutinin (HA) protein, which is responsible for binding to cells prior to infection. By studying the evolution of H1N1 from its first known appearance in 1918, the team discovered that the portion of HA responsible for actually attaching to cells varies much less than the other sections of the protein. After all, the protein must be able to attach to the cell.
Said Jianpeng Ma, a Rice professor in bioengineering with a joint appointment at BCM:
It becomes a weak link and provides us with a window into the virus that we can monitor. The virus's bottleneck is our opportunity.
The scientists hope that this information will lead to quicker and more reliable vaccines.By the way, have you ever wondered why this year’s flu strain is called ‘H1N1’? H1 means the virus contains HA protein number one. It also contains neuraminidase (NA) one, hence the N1. There are at least 16 different HA proteins and 10 NA proteins found in influenza.