Lecture 25

Question 1

What kind of antigen is usually involved in T-independent response?

Answer 1

carbohydrate

Question 2

What are the two types of plasma cells?

Answer 2

short lived and long lived?

Question 3

What are the characteristics of long lived plasma cells? (how are they generated and maintained)

Answer 3

• generated because of reactions in the germinal centre and produce antibody against protein antigens
• maintained in the bone marrow

Question 4

How does IgM act as an opsonin?

Answer 4

IgM binds to microorganisms and activates complement– C3b fragment acts as the opsonin

Question 5

What is the weakness of IgM?

Answer 5

it doesn’t get into the tissues (pentamer)

Question 6

Where is IgG mainly found?

Answer 6

in the blood

Question 7

How does IgA usually exist?

Answer 7

as a dimer in musocal secretions

Question 8

What isotypes would neutralize a virus particle or a protein toxin in the blood?

Answer 8

IgG IgM? check this

Question 9

What isotypes would neutralize a virus particle or a protein toxin in the tissue?

Answer 9

IgA? check this

Question 10

How do antibodies protect mucosal surfaces?

Answer 10

they prevent viruses from attaching to cells
or bacteria from attaching to mucosal surfaces.

Question 11

What is the point of a vaccine?

Answer 11

• memory T cells and B cells
• plasma cells
• going through the slow primary response without the illness

Question 12

What is the purpose of getting vaccinated frequently against the same pathogens when you were little?

Answer 12

• to generate class switched high affinity antibodies
• to increase the number of memory T cells and memory V cells
• igG antibodies can be transported from the blood and into tissues

Question 13

what is tetanolysin?

Answer 13

hemolysin that causes local destruction of tissues

Question 14

what is Tetanospasmin (TeNT)?

Answer 14

a potent neurotoxin that causes the disease tetanus
characterized by the widespread activation of motor neurons trigger severe and
painful muscle spasms throughout the body

Question 15

what is the AB exotoxin secreted by the tetanospasmin?

Answer 15

• B-chain of the toxin binds to the membrane of a periphery neuron and travels
  up the axon to an inhibitory neuron of the central nervous system.
• A-chain of the toxin enters the cell and prevents the release of inhibitory
  neurotransmitters

Question 16

How do they make the tetanus vaccine?

Answer 16

The tetanospasmin toxin is purified and inactivated in 40% formaldehyde for 4 –
6 weeks. The A-chain is removed prior to treatment.

Question 17

Why aren’t pure proteins immunogenic?

Answer 17

• they don’t have repeating epitopes on their surfaces
• in order to have a T dependent response, you need to activate DC, but can’t with a pure protein

Question 18

If we want B cells to produce high affinity, class-switched antibodies, what type
of T helper cell would we want?

Answer 18

Tfh, because you want a germinal centre