11. Animal Physiology : 11.1 Antibodies

Question 1

What is meant by immunity?

Answer 1

Immunity:

• recognition of self
• destroy foreign matter
• has memory cells that produce antibodies to recognise and eliminate threats

Question 2

What do the surface of human cells contain? What about cells of bacteria and viruses?

Answer 2

• human: large carbohydrates, glycoproteins, polypeptides

- Bacteria: molecules

Question 3

Define an antigen.

Answer 3

An antigen is any molecule that can trigger an immune response leading to the generation of antibodies.

Question 4

Give some examples of non-self molecules.

Answer 4

Viruses 
Fungi 
Parasite 
Bacteria 
Pollen 
Transplant of organs 
Foreign substances

Question 5

What is a rhesus factor?

Answer 5

Rh+ antigen found on the surface of red blood cells in people who are rhesus positive or Rh- when you lack it

Question 6

What does red blood cells have? Explain the three blood groups.

Answer 6

• have antigen H on surface
• A: molecule of N-acetylgalactosamine + antigen H
• B: molecule galactose
• AB: both molecules

Question 7

What is hemolysis?

Answer 7

• the breakage of the red blood cell’s membrane, leading to the release of the haemoglobin and other internal components into the surrounding fluid
• Agglutination causes hemolysis
• May lead to death

Question 8

Why is there a trigger once an antigen enters body?

Answer 8

• body needs to assure the antigen doesnt spread

- produce memory cells

Question 9

Explain the process of the immune system once an antigen enters the body.

Answer 9

1. Antigen is ingested by macrophages and B cells for processing
2. the macrophage interacts with T helper cell and activates it
3. T cell interacts with B cell, B cell divides to form clones of plasma and memory cells
4. Memory cells stays in body for long time to provide long term immunity to diseases

Question 10

What makes plasma cells well suited for producing antibodies againts the antigen?

Answer 10

Possess a lot of rough endoplasmic reticulum and a golgi apparatus

Question 11

Where are antibodies produced?

Answer 11

The memory B cells divide to form plasma cells. Produces once the immune system has reacted to the invasion of an antigen.

Question 12

What are the two variable regions of an antibody?

Answer 12

The part of the antibody which is specific to the antigen

The long and short chains are held together by disulphide bonds

Question 13

What is opsonization?

Answer 13

The coating of a pathogen with antibodies to promote and enhance phagocytosis

Question 14

When do complement proteins become activated?

Answer 14

When interaction with antigen, the function is fulfilled with antigens.

Question 15

How do antibodies help the destruction of pathogens?

Answer 15

• antigen is presented to complement protein
• the latter is split in two to give rise to the protein that binds to the membrane of pathogens
• it may increase its change of being engulfed by phagocytic cell
• may trigger the release of histamine
• these eliminates pathogens

Question 16

What occurs in a primary response and a secondary response?

Answer 16

• 1st: memory cells are produced to ensure that body remembers the infection
• 2nd: faster reaction of same antigens, memory cells divide by mitosis to form clones of plasma cells and more memory cells, divide faster becoz it doesnt need an antigen

Question 17

Why are vaccines used to trigger immunity?

Answer 17

• helps body get used to same antigen
• contains antigens that help produce memory cells that recognises the pathogen
• more cells are produced faster next time

Question 18

Why are flu shots against influenza virus necessary?

Answer 18

• the virus mutate quickly so body might not recognize

- mutations change antigens so need new type of vaccines each year

Question 19

What is an allergen and what occurs when there is an allergic reaction?

Answer 19

Allergen: substance that cause allergic reaction

- allergic reaction caused by histamines (strong response of immune system)

Question 20

Describe how histamines are released in response to allergens.

Answer 20

• released by basophils and mast cells in the connective tissues
• white blood cells and some proteins invade the affected tissues and engage the allergens
• can bind to membrane-bound histamine receptors and cause allergic reactions

Question 21

What are antihistamines?

Answer 21

Drugs that inhibit the action of histamine in the body by blocking the receptors of histamine

Question 22

Explain the process of an immune response to an allergen.

Answer 22

1. Allergen enters body
2. B cell comes into contact with the allergen
3. Plasma cells start producing the allergen-specific IgE, an antibody that circulates in the blood and binds to mast cells
4. This triggers the release of histamines and other cellular inflammatory compounds

Question 23

What are monoclonal antibodies used as?

Answer 23

Used as therapeutic agents in rheumatoid arthritis, B cell leukaemia and non-hodgkin’s lymphoma

Question 24

What are monoclonal antibodies?

Answer 24

Monospecific antibodies that target the same antigen, produced from one cloned plasma cell

They can recognise and bind to one specific region of the antigen

Question 25

What are polyclonal antibodies?

Answer 25

Antibodies secreted by plasma cells from different B cell lineages that have recognised different epitopes of one specific antigen

Question 26

How are monoclonal antibodies produced?

Answer 26

Fusion of a tumour cell with an antibody-producing plasma cell creates a hybridoma cell
A hybridoma cell creates monoclonal antibodies.

Question 27

How do pregnancy tests work?

Answer 27

1. Dipstick in urine of woman
2. If urine contains hCG, the anti hCG will bind to the hormone
3. If the hormone then binds to the monoclonal antibody, a blue line will appear and woman is pregnant.
4. If urine moves up to the dipstick, crosses another line ‘control line’
5. Control line: contains an antibody to the dye
6. If the second line is not indicated, the test is invalid

Question 28

Explain how monoclonal antibodies are produced.

Answer 28

NEED TO DO IT