Senses, Endocrine, Blood, Heart, and Reproductive System Practice Test

Vaccination introduces an antigen in a controlled way to prompt the body's adaptive immune response. This leads to artificial active immunity, because the immune system is actively stimulated to produce antibodies and, crucially, memory cells that remember the pathogen for future encounters. The vaccine trains the immune system without causing disease, so if the real pathogen is encountered later, the response is rapid and strong. Natural active immunity would come from actually getting sick, while natural passive immunity involves receiving antibodies from another source (like a mother), and artificial passive immunity involves giving antibodies directly.