Antigens & Receptors

Question 1

Immunogens

Answer 1

Molecules that elicit an immune response

Question 2

Stages of the immune response

Answer 2

1. Recognition phase - innate recognition
2. Activation phase - B/T-cell activation
3. Effector phase - pathogen is destroyed

Question 3

Secondary lymphoid tissue

Answer 3

Secondary lymphoid tissue is an important part of antigen recognition

It facilitates encounters between B/T cells and antigens

Lymph nodes = tissue infections
Spleen = blood infections

Question 4

Antigen definition

Answer 4

Any substance that binds to specific receptors on lymphocytes

Question 5

Epitope definition

Answer 5

The part of the antigen that binds to receptors

Question 6

Hapten definition

Answer 6

A small molecule that can act as an epitope but cannot elicit an immune response

Question 7

Immunogenicity

Answer 7

Immunogenicity describes the ability of an antigen to elicit an immune response

A larger molecule with more differences to self-proteins that enters via the subcutaneous route will be the most immunogenic

Question 8

Adjuvants

Answer 8

Adjuvants enhance the immune response to an antigen to make it more immunogenic

They are not natural components but are added to vaccines to improve success

• Freund’s adjuvant
• Alum

Question 9

B-cell receptors

Answer 9

B-cells bind to native antigen in solution

They recognise the 3D conformation of the antigen via the B-cell receptor

Question 10

T-cell receptors

Answer 10

T-cells bind linear arrays of antigen

The antigen must first be broken down by antigen-presenting cells to chains of approximately 9 amino acids