Immunity produced by transferring immune cells from a donor to a recipient is best described as what?

• A. Active immunity
• B. Adoptive immunity
• C. Passive immunity
• D. Natural immunity

Answer: (B)

Adoptive immunity is immunity produced by transferring immune cells from a donor to a recipient. When immune cells such as T cells or stem cells are moved into another person, those cells can actively respond to pathogens or malignant cells in the recipient and may establish immune memory with the donor-derived cells. This is different from active immunity, where the recipient’s own immune system is stimulated to respond (as with infection or vaccination) and from passive immunity, where antibodies or immune factors are provided from another source without the recipient generating their own response. Natural immunity refers to defenses that occur without any transfer of cells or deliberate stimulation, which is not what’s happening in adoptive transfers.