FIG. 7.

Postulated mechanism: MHC‐I molecule expression and NK cells influence the equilibrium between immunity and pathology during CTL‐mediated antiviral defense. During LCMV infection, if CTL response in the early phase of the infection is limited, resulting in viral persistence and T‐cell exhaustion, little CTL‐mediated immunopathology in the liver is observed (left). In H2‐D1^−/− deficient animals, an increased CTL immunity is induced while the viruses are still replicating, and virus‐infected liver cells are attacked by CTL; this leads to enhanced immunopathology (middle). NK‐cell depletion triggers rapid induction of CTL response. This leads to CTL mediated elimination of LCMV viruses in liver tissue and limited CTL mediated immunopathology (right).