(a) OT-I immune chimeras were challenged t.c. with SIINFEKL. 12 h later, OT-I cells and IFN-γ were visualized by immunofluorescence microscopy. (b) OT-I.Ifng+/+ and OT-I.Ifng−/− immune chimeras were challenged t.c. with SIINFEKL. 48 h later, CD8β+ cells were enumerated in FRT. (c) CD45.1+ memory OT-I cells were transferred to naïve recipients, which were then conjoined to Thy1.1+ P14 immune chimeric mice via parabiosis. 14-16 days after surgery, memory P14 cells were enumerated in both conjoined parabionts. (d) Parabionts (as in c) were challenged with gp33 t.c. and 48 h later OT-Is were quantified within 7 μm coronal sections through the entire FRT. Scale bars = 50 μm.. Data pooled from two independent experiments totaling 5-6 mice per group. *, P <0.001, unpaired two-tailed t-test, mean±SEM.