Figure 2.

Proposed mechanisms of viral-induced neuronal damage and the outcomes. 1. Infection of neurons with viruses leads to apoptosis, necrosis or autophagy (A). 2. Immune-mediated attack of neurons by viral-specific immunity by, for example, CD8⁺ T cells, leads to direct cytotoxic death, apoptosis, autophagy (A), dying back of the neurons (B) or neuronal death (C) and myelin damage. 3. Infection of cells (e.g. astrocytes) leads to so-called bystander damage as the result of release of cytokines or reactive oxygen species (ROS) that damage neurons in a variety of ways (A–C).