GZMB and infection: For bone marrow chimeric mice, intracellular staining and flow cytometric analysis demonstrated that Smad4-deficient Kb-ova+CD8+ splenic T cells exhibited decreased GzmB expression, but statistically unaffected IFN-γ expression, upon OVA peptide restimulation 5 days after the secondary infection, as compared to competing Smad4-sufficient cells (Figure 3f and Supplementary Figure S5).