Figure 4
From: Long-term adaptation of the influenza A virus by escaping cytotoxic T-cell recognition
CTL epitope dynamics.
Epitopes appear and disappear continuously in H1N1 (a) and H2N2-H3N2 (b), with the highest turnover in NP. Within years epitope gains and losses are correlated, due to annual variation in genetic drift. We calculate for each epitope the difference in the fraction of viruses harbouring the epitope in a given year and the year before. Summing over all positive (negative) differences of the fractions gives the total gain (loss).
