A 40-year-old man complains of having yellow skin and sclerae, abdominal tenderness, and dark urine. Physical examination reveals jaundice and mild hepatomegaly Laboratory studies demonstrate elevated serum bilirubin (3.1 mg/dL), decreased serum albumin (2.5 g/dL), and prolonged prothrombin time (17 seconds). Serologic tests reveal antibodies to hepatitis B core antigen (IgG anti-HBcAg). The serum is also positive for HBsAg and HBeAg. What glycoprotein on virally infected hepatocytes provides a target for cell-mediated cytotoxicity in the patient?
Class I HLA molecules. Class I molecules of the major histocompatibility complex present foreign peptides and are recognized by cytotoxic T lymphocytes during graft rejection or during cell-mediated killing of virus-infected cells. All tissues express class I molecules, whereas class II molecules (choice D) are displayed primarily on macrophages and B lymphocytes. CD4 and CD8 (choices A and B) are cell surface markers of helper and killer T lymphocytes, respectively. GlyCAM-1 (choice E) facilitates lymphocyte recirculation by providing a receptor for leukocyte attachment to high endothelial venules.Diagnosis: Chronic hepatitis B
CD4
CD8
Class I HLA molecules
Class II HLA molecules
Immunity