CD8A and infection: 10 days following infection, CD8+CD44+ splenocytes (S4 Fig) were co-stained with combinations of H-2Db/gp33(PE)-H-2Db/Y4F(APC) tetramers, H-2Db/gp33(PE)-H-2Db/V3P_Y4F(APC) tetramers or H-2Db/Y4F(PE)-H-2Db/V3P_Y4F(APC) tetramers in order to detect cross-reactive T cell populations (Fig 3B and 3C).