Immunity & Antibodies

Question 1

What’s the difference between naturally acquired and artificially acquired active immunity? (2)

Answer 1

1. Naturally acquired = during infection

2. Artificially acquired = received from vaccines

Question 2

What is the part in vaccines that helps give us immunity and how? (2)

Answer 2

1. Vaccines “prime” the immune system with weakened antigens
2. Still able to stimulate antibody production

Question 3

What do vaccines spare us from compared to naturally acquired immunity?

Answer 3

Spare us from the signs and symptoms of the disease that would otherwise occur during primary response

Question 4

Define: passive immunity

Answer 4

Immunity acquired through antibodies that are obtained by human or animal donor (eg. fetus)

Question 5

Where do immunogloblins come from? (2)

Answer 5

1. Secreted by activated B cells

2. Plasma offspring in response to an antigen

Question 6

Describe the structure of an antibody. (3)

Answer 6

1. Consists of 4 amino acid chains linked together by disulfide bonds
2. Each chain has a variable region (V) at one end
3. Each chain has a constant region at the other end

Question 7

What’s the difference between the V region and C region? (2)

Answer 7

1. V = forms an antigen-binding site to fit specific antigens
2. C = determines the type of antibody that will be formed

Question 8

List the 5 antibody classes. (5)

Answer 8

1. IgM
2. IgA
3. IgD
4. IgG
5. IgE

Question 9

Which antibodies are monomers and what makes them monomers? (2)

Answer 9

1. IgD, IgG, and IgE

2. They have the same basic V shape structure = monomers

Question 10

Which antibody is the most abundant in the blood plasma?

Answer 10

IgG

Question 11

What is special about IgG?

Answer 11

It is the only antibody that can cross the placenta barrier (passive process)

Question 12

What does IgE trigger?

Answer 12

Allergy reactions

Question 13

Does IgA occur as monomers or dimers?

Answer 13

Both

Question 14

What is a dimer?

Answer 14

2 linked monomers

Question 15

Where is IgA found and why? (2)

Answer 15

1. Found in the mucous and secretions (secretory)

2. Prevents pathogen entry

Question 16

How many monomers is IgM composed of and what is this called? (2)

Answer 16

1. IgM is a huge, 5-linked monomer

2. Pentamer

Question 17

List and briefly describe the 4 ways by which antibodies inactivate antigens. (4)

Answer 17

1. Complement fixation → binds to antibodies attached to cellular targets
2. Neutralization → binds to exotoxins (chemicals secreted by bacteria
3. Agglutination → clumps to foreign cells
4. Precipitation → cross-linking process in which antigen-antibody complexes become so large that they become insoluble and settle out of solution (Soluble antibody + soluble antigen = insoluble precipitate)