Figure 2
From: Long-term adaptation of the influenza A virus by escaping cytotoxic T-cell recognition
Decrease in the number of CTL epitopes over time.
(a) The number of CTL epitopes per virus decreases with 0.14 ± 0.01, 0.20 ± 0.06, and 0.40 ± 0.02, epitopes per year (SEM) in H1N1, H2N2, and H3N2, respectively (Methods). The number of CTL epitopes in avian viruses is larger than in recent human viruses (
H5N1, 
H7N9 and 
H9N2). (b) Protein specific CTL epitope dynamics showing a decrease in the number of epitopes in NP, matrix 1 protein (M1) and non-structural protein (NS1). The other IAV proteins are laid down in Supplementary Fig. S10. Reassortment events resulting in the appearance of novel proteins are marked by triangles. Subtype replacements are marked by vertical lines. The analysis is based on 7,347 whole-proteome sequenced viruses (Methods).
