Which type of immunity is primarily involved in recognizing and destroying cancer cells?

Cell-mediated immunity plays a crucial role in recognizing and eliminating cancer cells. This type of immunity relies primarily on T lymphocytes (T cells), particularly cytotoxic T cells, which have the ability to specifically identify and destroy cells that display abnormal markers, such as those presented by tumor antigens.

When cells become cancerous, they often express new antigens that are either not present in healthy cells or are expressed at abnormal levels. T cells can recognize these antigens, leading to their activation and proliferation. Once activated, cytotoxic T cells directly kill cancerous cells, while helper T cells assist in coordinating the immune response by stimulating other immune cells.

In contrast, humoral immunity, which involves B lymphocytes and the production of antibodies, is more geared toward responding to extracellular pathogens, such as bacteria and viruses, rather than the intracellular processes involved in cancer. Passive immunity refers to the transfer of pre-formed antibodies from one individual to another, providing immediate but temporary protection without activating the immune system fully. B lymphocyte immunity, while essential for antibody production, does not primarily address the direct destruction of cancerous cells, which is best managed by the cell-mediated arm of the immune system.