Chapter 1

Question 1

What did the term “immunity” mean HISTORICALLY?

Answer 1

Protection from infectious diseases.

Question 2

What is the immune system?

Answer 2

The set of cells and molecules responsible for immunity.

Question 3

What is an immune response?

Answer 3

It is the coordinated response of the immigration system to the introduction of foreign substances.

Question 4

What are examples of foreign substances that could trigger an immune response?

Answer 4

• A component of a microbe (a virus’ nucleic acid)
• Macromolecules
• Small chemicals (e.g. toxins)

Question 5

What is an antigen?

Answer 5

A foreign substance that induces an immune response.

Question 6

What is immunology?

Answer 6

It is the study of the immune response and the immune system.

Question 7

What are the types of immunity?

Answer 7

1. Innate immunity (natural immunity)
2. Adaptive immunity (acquired immunity)

Question 8

What is the function of innate immunity?

Answer 8

It provides an early line of defense against microbes.

Question 9

What are the components of innate immunity?

Answer 9

• Skin
• Lining of digestive and respiratory systems (epithelial surfaces)
• Phagocytic cells (neutrophils and natural killer cells)
• Blood proteins
• Cytokines

Question 10

What are cytokines?

Answer 10

They are proteins that regulate cell activities and communication of the innate immunity.

Question 11

True or false:
The innate immune response is SPECIFIC.

Answer 11

False. It is not specific and does not change after repeated exposure to foreign bodies.

Question 12

When does adaptive immunity become active?

Answer 12

When the innate immunity fails to fight the antigen, it activates adaptive immunity.

Question 13

What are the main properties of the adaptive immunity?

Answer 13

• Stimulated by exposure to antigen
• Increases with each exposure to a particular antigen
• Highly specific
• Has memory

Question 14

What are the main components of adaptive immunity?

Answer 14

1. Lymphocytes
2. Antibodies

Question 15

What are the types of adaptive immune responses?

Answer 15

1. Humoral immunity
2. Cell-mediated immunity (cellular immunity)

Question 16

Explain the two types of adaptive immunity.

Answer 16

1. Humoral immunity: mediated by the antibodies secreted by B-lymphocytes (antibodies are highly specific. Can only bind to extracellular antigens)
2. Cellular immunity: Mediated by T-lymphocytes against intracellular antigens (e.g. viruses and bacteria)