10.5 Vaccination Mechanics

Question 1

What is a live/attenuated vaccine?

Answer 1

Weakened infectious pathogen, used in vaccines

Question 2

Vaccination vs immunisation

Answer 2

Vaccination: taking vaccine (orally/injection)
Immunisation: The process of taking the vaccine and developing immunity to the pathogen

Question 3

Which type of vaccine (attenuated/dead) vaccine needs to be administered more times?

Answer 3

• Attenuated usually only once
• Dead more times (keep reminding the immune system)

Question 4

What cells are the first to be activated in order to mount an adaptive immune response?

Answer 4

CD4 cells

Question 5

What are the components of the TCR? Recall what they recognise

Answer 5

Alpha and beta. Recognise processed antigens

Question 6

Which cells permit CD8 cells and B naive cells to differentiate

Answer 6

T helper cells (this is why we need to activate CD4 first)

Question 7

Is natural immunity preferable?

Answer 7

Always yes. Once infected, you will acquire immunity and memory cells against pathogen.

Question 8

Which receptors recognise the butt end of antigens?

Answer 8

Fc receptors

Question 9

Which proteins are presented on MHC class 1?

Answer 9

All of them; even normal body ones

Question 10

Why is their a lag period for an immune response, even if vaccinated?

Answer 10

Lag time for B and T cells to migrate to secondary lymph tissue at site of infection

Question 11

Which type of vaccine gives humoral immunity, and which gives both humoral and cell mediated immunity?

Answer 11

Attenuated gives both, since it is alive, and can move into cells

Question 12

What are the four types of vaccines?

Answer 12

• Live attenuated
• Inactivated
• Purified Subunit
• Cloned

Question 13

Can an activated CD4 T cell activate any B cell? How does it do this?

Answer 13

No; only the B cells that have independently discovered the same antigen as the dendritic cells in the periphery. Like dendritic cells, these are expressed on MHC class 2

It does this using cytokines

Question 14

Which type of antibody do plasma cells express?

Answer 14

IgM (pentameric)

Question 15

What type of Ig is expressed on B memory cells?

Answer 15

IgG

Question 16

What is “affinity maturation”

Answer 16

When B memory cells are formed, they change their recognition sites are improved

Question 17

Why does the IgM peak go down?

Answer 17

The cells that are making IgM begin making IgG

Question 18

How are attenuated pathogens produced

Answer 18

Passaged through many wells of monolayers of cells and culture fluid until they mutate and are no longer dangerous.

Question 19

Pros and cons of live attenuated vaccines

Answer 19

Pros: Only need one does
Cons: Reversion to wild type

Question 20

Pros and cons of inactivated vaccine

Answer 20

Pros: Stimulate humoral immunity
Cons: Little to no cell mediated immunity, multiple doses

Question 21

Pros and cons of purified subunit vaccines

Answer 21

Pros: stimulate humoral immunity
Cons: minimal/no cell mediated immunity

Question 22

Pros and cons of cloned vaccines (e.g. mRNA vaccines)

Answer 22

Pros: Stimulates humoral immunity, and no reversion to wildtype
Cons: Multiple doses required

Question 23

What is passive immunity

Answer 23

• Direct injection of antibodies (from someone who actually has the active immunity)
• Antibodies are found in the serum after centrifuging

Question 24

Why can’t B cells just activate themselves via autocrine signalling?

Answer 24

We need verification by T cells to minimise chances of autoimmunity. Therefore, the screening of naive B cells is not 100%. This is also why B cells are T cells are educated separately.