Macrophage engulfs microbe, encloses it within endocytic vesicle, and enzymatically breaks it down to release peptide fragments. Fragments are antigenic. Induced Immunity can be acquired naturally through infection or artificially by medical intervention. Active Immunity Is Long-Lived a. Develops naturally after person is infected with microbe. Artificial immunization against foreign agent when person is healthy prevents future infection.
Immunization uses vaccines , substances that contain antigens to which immune system can respond.
Genetically engineered bacteria can produce just the surface protein of a microbe. Several vaccines can be produced for a combination vaccination, utilizing surface proteins from several disease agents. Provides longer lasting protection. Primary response is gradual. It takes several days before antibodies appear.