AIPGMEE 2016 Pathology MCQ

A 33-year-old man has experienced nausea and vomiting and has become mildly icteric over the past week. On physical examination, his temperature is 37.4° C. Laboratory studies show serum AST of 208 U/L and ALT of 274 U/L. Serologic findings for HBsAg and HBcAb are positive.
A liver biopsy specimen examined microscopically shows focal death of hepatocytes with a portal inflammatory cell infiltrate. Which of the following is the most likely mechanism by which his liver cell injury occurs under these conditions?
A Activated macrophage cytokine release
B Antibody-mediated destruction of HBsAg-expressing liver cells
C CD4+ lymphocyte recognition of circulating HBsAg
D CD8+ lymphocyte recognition of viral peptide presented by MHC class I molecules
E NK cell recognition of viral peptide presented by MHC class II molecules
Answer - D

Virus-infected cells are recognized and killed by
cytotoxic
CD8+ T cells. The T cell receptor on the CD8+ T cells
binds to the complex of viral peptide and MHC class I molecules
displayed on the surface of the infected cell. Natural
killer (NK) cells also recognize MHC class I molecules with
self-peptides, but this self-recognition inhibits NK cell killing.
Viruses that inhibit MHC I expression of peptides may
hide from cytotoxic cells, but not from NK cells. The other
listed options are not the major immune response to hepatitis
viral infection