Question

Injecting a person with a vaccine containing heat-killed microorganisms provides: A. active immunity by giving antibodies. B. passive immunity by stimulating the macrophages to produce antibodies. C. passive immunity by providing memory cells. D. active immunity by stimulating the body’s production of antibodies and memory cells. E. active immunity by stimulating the macrophages to produce antibodies.

Answer 1

Injecting a person with a vaccine containing heat-killed microorganisms provides active immunity by stimulating the body’s production of antibodies and memory cells. (option D.)

What is a vaccine?

• A vaccine is a serum injected into the body which contains weakened(attenuated) or dead microorganisms.
• Since it is only a small dose of weakened/dead microorganisms, it does not cause a serious infection.
• It works on the principle of the body's acquired immunity. It also relies on the body's memory cells.

How does a vaccine work?

• When a small dose of weakened/dead microorganisms is introduced into the bloodstream, antibodies are formed by the lymphocytes.
• This primary response is weak and slow as the lymphocytes have come in contact with the pathogen for the first time.
• This acquired immunity also can remember the first attack by a pathogen. Thus, when the body comes in contact with the same pathogen later, the infection triggers a secondary response.
• The secondary response is more accelerated and stronger as compared to the primary response. Thus, our body is protected from a particular pathogen.
• This type of immunity is called active because antibodies are produced by our body. In passive immunity, preformed antibodies are injected into the bloodstream.

So, option D. Active immunity by stimulating the body’s production of antibodies and memory cells is correct.