Function and phenotype of pearl CTL at different time points after infection. (A, B) Cytokine production of C57BL/6, pearl, and PKO CTL was analyzed by flow cytometry on days 8 and 12 after infection with 200 pfu of LCMV. CTL were stained for (A) IFN-γ and (B) TNF-α production after peptide stimulation in vitro. Representative FACS plots are shown at the top and (A) frequencies of IFN-γ^hi cells among IFN-γ⁺ CD8 T cells and (B) frequencies of TNF-α⁺ cells among CD8 T cells are shown at the bottom. Surface expression of (C) KLRG1 and CD127 and (D) CD44 and CD62L on CTL are depicted as representative FACS plots (top) and frequencies are shown (bottom). Representative data from 1 of 2 independent experiments with 3-4 mice per group are shown. For IFN-γ and TNF-α (day 8) pooled data from two independent experiments are shown. n.s. indicates not significant (P > .05); *P < .05; **P < .01; ***P < .001.