Cytotoxic T-cells may attack which of the following?

Cytotoxic T-cells, also known as CD8+ T-cells, play a crucial role in the immune response by specifically targeting cells that present foreign antigens, which typically indicates infection or abnormal function. They are particularly effective against antigen-bearing cells, such as virus-infected cells and cancer cells.

When a cell becomes infected by a virus or transforms into a cancerous state, it often presents abnormal or foreign proteins (antigens) on its surface. Cytotoxic T-cells recognize these antigens through their T-cell receptors, leading them to bind to and destroy the infected or abnormal cells. This function is essential for maintaining the body's defense against intracellular pathogens and malignant cells.

In contrast, while B-cells and fungus cells may also be targets of the immune response, they are not specifically recognized and attacked by cytotoxic T-cells in the same direct manner. Instead, B-cells produce antibodies to neutralize pathogens, and fungus cells invoke other parts of the immune system. Therefore, the capability of cytotoxic T-cells to attack antigen-bearing cells underscores their specialized role within the immune system.