A vaccine is effective because ________.
A) B-lymphocytes are unable to mount an immune response the first time they are exposed to a new pathogen
B) the secondary response of the adaptive immunity is faster and more efficient the primary response
C) the vaccine contains the lymphocytes necessary to fight infection
D) the vaccine contains the antibodies necessary to fight infection

Question

Quizplus · Accepted Answer

A vaccine works by priming the immune system with a weakened or inactivated form of a pathogen, which allows the body to produce a memory of the pathogen and generate a faster and more efficient secondary immune response if it encounters the actual pathogen in the future. This is because during the primary immune response, B-lymphocytes undergo differentiation and activation, whereas during the secondary response, memory B-cells are already present and can rapidly produce large amounts of specific antibodies.

A Vaccine Is Effective Because ________