Immunity and immune deficiencies

Question 1

Is childhood immunisation an active or passive form of protection against a disease? Justify your answer.

Answer 1

Active protection: The child is producing its own antibodies and memory cells.

Question 2

What is an immunisation?

Answer 2

• Immunisation is the term used for the natural and artificial active exposure to the foreign antigen whereas vaccination is only the artificial exposure
• Vaccination is a type of immunization, but immunization is not necessarily vaccination alone.

Question 3

What is a vaccination?

Answer 3

Vaccination is the administration of antigenic material to stimulate an individual’s immune system to develop adaptive immunity to a pathogen.
Is a form of active artificial immunity.

Question 4

What is the difference between natural immunity and artificial natural immunity?

Answer 4

• natural active: means there will be a direct exposure to disease conditions whereas artificial active immunity you are given live-attenuated antigens for your body to form antibodies to attack the antigens
• natural active: antibodies produced after exposure to infection whereas artificial active antibodies are formed after immunisation of attenuated antigens

Question 5

What is the difference between active and passive immunity?

Answer 5

• Active Immunity results in the production of memory B and T cells whereas passive immunity does not.
• Active immunity: antibodies directly form upon contact with an antigen whereas direct transfer of antibody from one person to another

Question 6

What is active immunity?

Answer 6

Immunity that develops after the immune system responds to being exposed to microbes or foreign substances.

Question 7

What is the difference between natural and artificial passive immunity?

Answer 7

• Naturally acquired immunity is caused by natural exposure to microbes whereas artificial is a result of medical treatment.
• Natural passive immunity occurs when antibodies are acquired by baby across the placenta or in mothers milk

Question 8

What is passive immunity?

Answer 8

Immunity acquired when antibodies are transferred from one person to another.

Question 9

Many immunisation schedules include regular booster injections. Explain how these work and why they are necessary.

Answer 9

How: To produce more memory B cells
Why: Memory cells are short lived

Since this form of immunity is not long lasting, there is a need for regular exposure to the antigen in order for the body to retain its memory. A booster re-exposes the body to the pathogen to produce more of the specific antibodies and b memory cells.

Question 10

Vaccines contain dead or attenuated (changed) cells of the disease-causing organisms. Explain why dead or attenuated cells are effective as a vaccine.

Answer 10

The dead or attenuated cells are still identified as foreign and retain antigenic property to stimulate the production of antibodies against it when injected.

Question 11

Explain how vaccination leads to the production of memory cells. (2)

Answer 11

• After vaccination, the antigens combine with some of the B cells in the individual receiving the vaccination and cause the B cells to reproduce rapidly resulting in large numbers of cloned cells (clonal expansion).
• Many of these cloned cells form plasma cells but some form B memory cells which can survive for many years, and react immediately to produce antibodies if the person is reinfected with the particular antigen.