Cell-mediated immunity primarily involves which type of cell?

Cell-mediated immunity primarily involves T lymphocytes, which play a crucial role in the adaptive immune response. T lymphocytes are responsible for directly attacking infected or cancerous cells, as well as coordinating the immune response by signaling other cells. They differentiate into various types, such as helper T cells, which assist other immune cells, and cytotoxic T cells, which directly kill infected or malignant cells.

Unlike B lymphocytes, which are mainly involved in humoral immunity and produce antibodies against pathogens, T lymphocytes provide a means of surveillance and destruction of infected cells. Macrophages do engage in phagocytosis and can present antigens to T cells, but they do not carry out the specific cell-mediated response themselves. Red blood cells lack any direct role in immune response as they are primarily responsible for oxygen transport. Therefore, T lymphocytes are central to cell-mediated immunity, making them the correct choice in this context.