A Universal Influenza Vaccine?

The Influenza A genome contains 11 proteins: hemagglutinin (HA), neuramidase (NA), nucleoprotein (NP), M1, M2, NS1, PA, PB1, (polymerase basic 1), PB1-F2 and PB2[1]. The first two form the basis of the H and N distinctions in the different type of Influenza, for example, H5N1 or H1N1.

The proteins of the influenza virus are constantly mutating via antigenic drift (small incremental changes) and antigenic shifts (great leaps of change). That means that creating a vaccine for next years’ influenza is always something of a gamble.

Now scientists say they have made a significant leap towards creating a vaccine that would protect against every possible type of influenza. They had a hypothesis that the human immune system would not be able to recognize the ever changing outer shell of the virus, but the core may have been encountered before in other influenza viruses.

The genetic material on the inside is common to many strains of influenza. Vaccine researchers now believe targeting the core of the virus may be the way to develop a universal vaccine[2].

A specific part of the immune system, called T-cells, is thought to be able to recognize proteins in the core. The team compared levels of one kind of T-cells at the start of the pandemic with symptoms of influenza N1H1 in 342 staff and students at the university. They showed that the higher the levels of the T-cells a patient had, the milder their symptoms were.

Prof Lalvani, who led the study, said: "It's a blueprint for a vaccine. We know the exact subgroup of the immune system and we've identified the key fragments in the internal core of the virus. We have the know-how, we know what needs to be in the vaccine and we can just get on and do it."

Yet the researchers admit it is "generally harder" to develop a T-cell vaccine than provoke an antibody response. Which means this route may be flawed.

[1] Ghedin et al: Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution in Nature - 2005
[2] Sridhar et al: Cellular immune correlates of protection against symptomatic pandemic influenza in Nature - 2013