Nonfatal HLH progression in Stx11^−/− mice. (A-B) Stx11^+/− (○) and Stx11^−/− (●) mice were infected intravenously with 200 PFU LCMV, and body weights were followed for 36 days after infection (A) and determined on day 180 after LCMV infection (B), respectively. (C) Frequency of LCMV-specific CD8 T cells was determined by GP33-tetramer staining. (D) CD8 T-cell differentiation into effector subpopulations was analyzed by staining for KLRG1 and CD127 expression to discriminate CTL with a short-lived effector cell or memory effector precursor cell phenotype. (E) Virus titers in the indicated organs were determined on days 36 and 180 after infection. (F) IFN-γ expression of CD8 T cells was measured after 4 hours of in vitro restimulation with GP33-peptide on day 12 after infection. IFN-γ expression of Stx11^−/− CD8 T cells was statistically compared with Stx11^+/− and PKO CD8 T cells, respectively. Horizontal lines in graphs represent mean values. Data (mean ± SEM) represent at least 2 independent experiments with 3 mice per group. ***P < .001 (Student unpaired t test). n.s. indicates not significant.