On day 40 post infection, the number of OT-I TRM CD8+ T cells was reduced in skin where lower affinity peptides were presented (Fig. 2h), suggesting that the strength of TCR stimulation required for IFNγ expression in the skin is largely equivalent to that required for subsequent TRM CD8+ T cell differentiation, whereas the number of memory OT-I CD8+ T cells in the circulation was not impacted (Fig. 2i). This evidence concerns the gene CD8A and infection.