PRF1 and infection: In addition, T cell receptor beta chain (Tcrb)−/−→ Sod1−/− (Figure 4C) and perforin 1 (Prf1)−/−→ Sod1−/− bone marrow chimeric mice (Figure 4D), lacking either αβ T cells or the hematopoietically-expressed cytolytic effector protein PRF1 respectively, exhibited liver damage similar to controls upon infection.