CD8+ T-cell-mediated response to Listeria monocytogenes taken up in the liver and replicating within hepatocytes.

Like most other organisms that enter the bloodstream, the bulk of Listeria monocytogenes injected i.v. into mice is taken up by the liver. Listeriae not killed rapidly by infiltrating neutrophils are internalized by hepatocytes which constitute the principal site of intracellular replication in the liver. CD8+ T cells play a critical role in eliminating infected hepatocytes and resolving listerial infections of the liver; the specific mechanisms involved are not understood fully. Here, we review recent data implicating the cytolytic activities expressed by MHC class Ia- and class Ib-restricted CD8+ T cells in host resistance to Listeria. Evidence demonstrating the perforin- and/or Fas ligand-dependent induction of caspase activity and the resultant apoptosis of Listeria-infected hepatocytes is discussed.