Which term refers to a substance that provides immunity to a specific disease?

A vaccine refers to a substance that stimulates the body's immune response against a specific disease. Vaccines contain components that resemble the disease-causing organism, such as weakened or inactivated pathogens, or pieces of the pathogen like proteins. When administered, they prompt the immune system to recognize these components as foreign, leading to the development of antibodies and memory cells. As a result, if the individual is later exposed to the actual disease, their immune system is prepared to fight it off more effectively.

In contrast, antibodies are proteins produced by the immune system in response to an infection or vaccine, helping to neutralize pathogens. Antigens are foreign substances, usually on the surface of pathogens, that trigger an immune response but are not inherently protective on their own. Antibiotics are medications used to treat bacterial infections and do not provide immunity to diseases. Thus, the term that specifically designates a substance offering immunity is clearly the vaccine.