Which scenario best illustrates adoptive immunity?

• A. The recipient's own immune system responding to a vaccine
• B. Transfer of immune cells from a donor to a recipient
• C. Infection induced innate response
• D. Natural selection of immune genes

Answer: (B)

Adoptive immunity is when protective immune elements are transferred from one individual to another, providing the recipient with donor-derived immune components. Transferring immune cells from a donor to a recipient fits this concept perfectly because the recipient gains adaptive immune cells that can recognize and respond to pathogens based on the donor’s immune repertoire. This is different from vaccines, where the recipient’s own immune system is primed to develop a response (active immunity) rather than receiving pre-made immune cells. It also differs from an infection-triggered innate response, which is non-specific and not about transferring memory or specialized immune cells. It’s also not about evolutionary changes in immune genes, which is a population-level process, not an individual transfer of immunity.