Chapter 7 Set 7

Question 1

What are Antigens? Are they small/large? Provide 3 examples of them.

Answer 1

A substance capable of producing an immune response. They are usually large molecules.

Examples include:
Whole microorganism
Part of the protein coat
A toxin produced by a pathogen
Foreign tissue (eg donor blood or tissue)

Question 2

Can the immune system distinguish between self and non-self antigens? How?

Answer 2

Yes. The body’s distingushes between self-antigens and non-self antigens.

Question 3

What are APCs? What are some examples?

Answer 3

Antigen Presenting Cells (APC)s are phagocytes, that ingest pathogens as part of the non-specific response.

Some examples of APC include:
Macrophages
Some lymphocytes

Question 4

How do APCs work?

Answer 4

1st. They ingest pathogens as part of the non-specific response.

2nd. They present the antigen (part of the pathogen that the immune system recognises) on their surface.

3rd. “present” the antigen to lymphocytes which are involved in the specific immune response.

Question 5

What are lymphocytes? Where are they found and produced?

Answer 5

White blood cells that are involved in both non-specific and specific defence.

Can be found:
In blood circulation
In tissues
In lymph nodes

Produced in bone marrow.

Question 6

What are B-Cells? Where are they found, made, and mature.

Answer 6

B-Cells are Lymphocytes involved in Antibody-Mediated Immunity.
Made in bone marrow
Mature in bone marrow
Move to lymphoid tissues and blood
Involved in anti-body mediated (humoral) immunity

Question 7

At what moment does Antibody-Mediated Immunity work?

Answer 7

Deals with pathogens before entry to cells.

Question 8

What is the 1st Step in AMI? (Production)

Answer 8

B-lymphocytes produced in lymphoid tissue

Question 9

What is the 2nd Step in AMI?

Answer 9

Antigen Presenting Cell (APC) which has engulfed and destroyed pathogen, presents the antigenic site for that pathogen on its surface.

Question 10

What is the 3rd Step in AMI?

Answer 10

The APC presents the antigen to a B-cell with a matching receptor. The B-cell becomes sensitised, enlarges and divides, producing many more sensitised B-cells.

Question 11

What is the 4th Step in AMI? (Transform)

Answer 11

Most of these sensitised B-cells become plasma cells.

Question 12

What is the 5th Step in AMI?

Answer 12

The plasma cells produce antibody specific for the antigen originally presented by the APC.

Question 13

What is the 6th Step in AMI?

Answer 13

The antibody is released, and is then able to bind to antigenic sites on the same pathogens as the one originally presented by the APC, neutralising the pathogen.

Question 14

What is the 7th Step in AMI?

Answer 14

Sensitised Memory B-cells remain in circulation, so that the response proceeds more quickly if the pathogen is encountered again.

Question 15

What is an example of a disease that is killed with AMI?

Answer 15

Measles antibody is produced in response to the antigenic site on the measles virus after it enters the body.

Question 16

What are 4 different ways an antibody ‘neutralises’ a pathogen?

Answer 16

1: Binding to active sites so virus/bacteria/toxin can no longer cause damage.
2: Sticking multiple pathogens together – agglutination
3: Reacting with soluble antigens to make them insoluble
4: Inhibiting reactions in foreign cells or compounds, leading to cell breakdown

Question 17

What is the primary immune response? What 2 things occur then?

Answer 17

Primary Response: the first time a specific antigen is encountered.
Slower response – takes several days to clone B-cells and manufacture antibodies.
Symptoms occur and are then overcome.

Question 18

What is the secondary response, what occurs then?

Answer 18

Secondary Response: subsequent times that the specific antigen is encountered.
Faster response – memory cells allow for faster recognition of antigens and therefore antibody release before signs of illness develop.