How does the hepatitis A virus injure hepatocytes?

Hepatitis A virus (HAV) primarily injures hepatocytes (liver cells) through the immune response it elicits rather than through direct viral cytotoxicity. The liver is an immune-privileged organ, and when HAV infects hepatocytes, it leads to the activation of the immune system. Specifically, HAV-specific CD8+ T cells and Natural Killer (NK) cells play significant roles in detecting and eliminating infected hepatocytes.

These cytotoxic immune cells respond to viral antigens presented on the surface of infected liver cells. Once activated, they release perforins and granzymes, which induce apoptosis in the infected cells. This immune-mediated destruction is a primary mechanism of liver damage in hepatitis infections. It's important to note that while HAV does replicate within hepatocytes, the direct cytotoxic effects of the virus itself are generally minimal compared to the damage caused by the immune response.

In contrast, other mechanisms mentioned in the options, such as autoimmune responses or oxidative stress, although they can contribute to liver injury in different contexts or other types of viral hepatitis, are not the primary means by which HAV causes damage to the liver in the acute phase of infection. Thus, the role of HAV-specific CD8+ T cells and NK cells is central