Analysing the expression of various lineage markers in the clusters showed that CD8+ T cells in cluster 6 expressed no examined markers, while clusters 0 and 4, enriched in the d9 sample, expressed high levels of Klrg1 and Gzmb indicating effector differentiation (Fig 1E), whereas the Il7r transcript was expressed more in the other clusters representing naïve and memory phases of infection (Fig 1E). Here, GZMB is linked to infection.