Antigenic cartography of human and swine influenza A(H3N2) viruses

Influenza viruses are classic examples of antigenically variable pathogens and have a seemingly endless capacity to evolve in order to evade the immune response. The degree to which immunity induced by one strain is effective against another is mostly dependent on the antigenic difference between the strains. Antigenic drift is thus both the root cause of the enormous public health burden of influenza epidemics, and a primary reason why the virus is such a fascinating pathogen from a scientific perspective. Antigenic cartography is a new technique that can be used to analyse binding assay data and to obtain a detailed quantitative visualization of antigenic differences among pathogens. We provide a brief summary of antigenic cartography and its use to analyse the antigenic drift of influenza A(H3N2) viruses in humans and swine.