Figure 4.

High levels of stable transgene chimerism in transplanted Prf1^−/− mice and significant correction of HLH phenotype. Twelve weeks posttransplantation (before LCMV challenge), peripheral blood from mice was analyzed for (a) gene-modified NK cell chimerism in peripheral blood by flow cytometry for tNGFR expression. Statistics were done by one-way Dunnett's analysis of variance (ANOVA) and (b) vector copy number (VCN) on leukocyte DNA by qPCR. Median tNGFR expression of VCN is indicated by the horizontal bars. Statistics were done by Mann-Whitney U test. At 16 weeks transplanted mice were challenged with LCMV. (c) Splenocytes were tested for cytotoxic function by a ⁵¹Cr release assay with GP-33-loaded EL4 target cells. Error bars represent the SEM from 8 to 12 mice per group or three mice in the TxPrf1^−/− group. Statistics were done by two-way Dunnett's ANOVA. Inset: Percent tNGFR expression in CD8⁺ cells in the splenocytes 8 days after LCMV challenge (n = 10 experiments). Horizontal bars represent median values in each group. For the inset, statistics were done by one-way Dunnett's ANOVA. (d) Serum IFN-γ levels were measured in peripheral blood 8 days after LCMV infection and normalized to VCN in peripheral blood preinfection. Statistics were done by one-way Dunnett's ANOVA. Error bars represent the SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.