Which statement best describes passive immunity?

Which statement best describes passive immunity?

• A. It is produced by the host's own immune system
• B. It involves antibodies produced in a donor animal
• C. It is long-lasting
• D. It develops after exposure to a pathogen

Answer: (B)

Passive immunity is the transfer of ready-made antibodies from one individual to another, giving immediate protection without the recipient’s immune system having to respond. Because the antibodies come from a donor, the protection is temporary as those antibodies are eventually cleared from circulation. That’s why the correct statement says it involves antibodies produced in a donor animal. In contrast, active immunity relies on the recipient’s own immune system to respond to an antigen, developing protection that is longer-lasting and often accompanied by immunologic memory. It develops after exposure to a pathogen or after vaccination.

Passive immunity is the transfer of ready-made antibodies from one individual to another, giving immediate protection without the recipient’s immune system having to respond. Because the antibodies come from a donor, the protection is temporary as those antibodies are eventually cleared from circulation. That’s why the correct statement says it involves antibodies produced in a donor animal. In contrast, active immunity relies on the recipient’s own immune system to respond to an antigen, developing protection that is longer-lasting and often accompanied by immunologic memory. It develops after exposure to a pathogen or after vaccination.