Blood and Body Defences

Question 1

What is the principle behind giving multiple boosters of a vaccine, for example three, as opposed to one or two?

Answer 1

The more boosters, the greater the level of Memory T cells are produced / remain for longer / react quicker

Question 2

Give examples of conditions where there is Hyperractivity / Reactivity against harmless agents

Answer 2

Allergies
Asthma
Septic shock / Analphylactic shock
Chronic inflammation

Question 3

Define “autoimmunity”

Answer 3

Reactivity against self

Question 4

Define the two signal model of T cell activation - what are the two signals?

Answer 4

1. Signal 1: Binding of TCR to Peptide-MHC complex

2. Signal 2: Binding of CD28 on T cells to co-stimulatory molecules CD80 or CD86

Question 5

According to the two signal model of T cell activation, if Signal 1 is only present - what happens?

Answer 5

Anergy

Question 6

The immunological synapse possesses two interfaces - what are these interfaces called?

Answer 6

p-SMAC (peripheral)

c-SMAC (centre)

Question 7

Evidence suggests there’s also a third signal for T Cell activation - what is it?

Answer 7

Cytokines

Question 8

Describe the negative regulator of T cell activation (CTLA-4 / PD-1)

Answer 8

CTLA-4 outcomes CD28 for CD80 / CD86, and also activates Phosphatases (shp1) to inhibit downstream TCR signalling

PD-1 also induces expression of phosphatases (shp1 and shp2)

Question 9

What is the mechanism of action of Rapamysin?

Answer 9

Inhibits proliferation of T cells by blocking mTOR activation