What primarily accounts for the histological features of infectious mononucleosis caused by Epstein-Barr virus?

The histological features of infectious mononucleosis, particularly those resulting from Epstein-Barr virus (EBV), are primarily attributed to the proliferation of cytotoxic T cells. When EBV infects B cells, the immune response is initiated, and the body mounts a response to control the infection. Cytotoxic T cells (also known as CD8+ T cells) are activated to target and eliminate these infected B cells, leading to an increase in their numbers, which is prominently observed in the lymphoid tissue.

This proliferation of cytotoxic T cells results in characteristic histological changes, such as the presence of atypical lymphocytes and an increase in lymphoid follicles in the lymph nodes. The activation of these T cells is a hallmark of the immune response to EBV and is responsible for the overall symptoms and features associated with infectious mononucleosis.

While B-cell proliferation does occur as part of the infection process, it is the cytotoxic T cells' response that is more directly responsible for the distinct histologic changes seen in this condition. The other concepts, such as the primary humoral immune response or oncogene activation, play a role in the overall infection process or pathogenesis but do not account for the specific histological features associated with infectious