Immunology 2

Question 1

What is a hapten?

Answer 1

An antigen that needs covalent linkage to a carrier to stimulate an immune response eg penicillin

Question 2

What is a superantigen?

Answer 2

Bind Vbeta chain of the TCR, bypassing the need for MHC to present the antigen–>large number polyclonal T lymphocytes activated

Question 3

How does adrenaline work?

Answer 3

Act on beta and alpha receptors to cause vasoconstriction and bronchodilation
Downregulate histamine and tryptase release

Question 4

MOA sodium chromoglycate

Answer 4

stabilise mast cell

prevent degranulation by blocking calcium influx

Question 5

What has to be done before skin prick testing?

Answer 5

hold antihistamines 4-7 days

RAST can be done on antihistamines

Question 6

Of T reg cells, IL-10 does what?

Answer 6

Promote IgG4

Question 7

Of T reg cells, TGF beta does what?

Answer 7

promotes IgA

Question 8

What are the three sets of things that bind between APC and T cell?

Answer 8

TCR binds to MHC on APC
CD40L on T cell binds CD40 on APC
CD28 on T cell binds B7 AKA CD80/86 on APC
Note CTLA4 on T cell can also bind CD80/86

Question 9

MHC1 made up of what molecules?

Answer 9

3 alpha chains
and
beta 2 microglobulin

Question 10

MHC2 made up of what molecules?

Answer 10

2 alpha

2 beta

Question 11

Which cells express MCH class 2?

Answer 11

Macrophages
dendritic cells
B lymphocytes
Thymic epithelia
Activated T cells

Question 12

The most common autoimmune disease?

Answer 12

Coeliac then Graves

Question 13

What does GAD actually do?

Answer 13

Involved in glutamate metabolism

Question 14

Increase age of onset of type 1 DM….

Answer 14

reducing incidence of multiple antibodies being positive
Later onset DM- more GAD, less anti insulin
ie LADA often only GAD positive with intermediate risk HLA

Question 15

Breast feeding does what to celiac risk?

Answer 15

Lowers

Too much early gluten increases risk

Question 16

Chronic atrophic gastritis- antral vs corpus

Answer 16

antral gastritis- H pylori

Corpus gastritis- autoimmune

Question 17

What is thought to be a biomarker of corpus atrophy after you have pernicious anaemia?

Answer 17

Anti gastrin Ab

Question 18

Which DM1 ab is most sens and spec?

Answer 18

anti GAD

Question 19

Mechanism of hyponatraemia in secondary or tertiary adrenal insufficiency?

Answer 19

ACTH concentration low or normal
Plasma renin and aldosterone unaffeted, though if long standing can sometimes getmineralocort def
Serum Na often reduced because of reduced inhibition of ADH secretion by no cortisol

Question 20

Association between rotavirus and celiac disease?

Answer 20

Yes, often precedes

Question 21

Briefly, what is IPEX?

Answer 21

monogenic FOXP3 geen mutation
Over half have DM1
also enteropathy
X linked

Question 22

Crohn’s technically not an autoimmune disease, more of an/….

Answer 22

autoinflammatory disease!
INNATE not adaptive immune damage
NOD2 mutation linked to aberrant innate immune response

Question 23

BASILIXIMAB does what?

Answer 23

IL-2 blocker

Question 24

Lipopolysaccharides expressed on what cells?

Answer 24

Example of a PAMP- pathogen assoc molecular protein

Seen on gram negative bugs

Question 25

Lipoteichoic acids expressed on what cells?

Answer 25

Gram positives, example of a PAMP.

Question 26

What are PRRs?

Answer 26

Pattern recognition receptors- recognise PAMPs - TLR recognise bacterial cell wall lipid outside cell - NOD LR recognise bacterial cell wall lipid inside cell - RIG like receptors recognise viral RNA in cell Triggering activates cell

Question 27

What are toll like receptors?

Answer 27

cell surface proteins responsible for host defense. When in contact with microbial peptide, acts via NFkB pathway to upregulate antibicrobial peptides- CK, costim molecules. Responsible for shock in gram neg sepsis when LPS binds LTR4

Question 28

What is MBL?

Answer 28

used to be called the universal Ab an acute phase reactant that is structurally and functionally similar to C1q Cleaves C4 and C2 for MBL complement pathway Also an opsonin

Question 29

Which are the only cells in the body not to express MHC I?

Answer 29

neuronal cells | RBCS- not attacked because lack activating receptor

Question 30

What is the significance of CCR5 delta 32 in HIV?

Answer 30

This is the molecule tht R5 strains of HIV virus use for entry Heterozygote- slowed disease progression Homozygote- resistant to infection R5 strains infect macrophages and T cells X4 strains infect T cells only

Question 31

What is a normal K:l ratio ?

Answer 31

2:1

Question 32

How do the different Igs differ?

Answer 32

Different appearance of the hinge regions (length) between the Fab and Fc of the Ig

Question 33

Fc gamma receptors are found where?

Answer 33

On phagocytic cells | Hence IgG is the most important opsoniser.

Question 34

Which Ig can get to fetus?

Answer 34

IgG

Question 35

What is the role of FcRn?

Answer 35

This is the neonatal Fc receptor gut of infant lining cells have these receptors- take up igs but do not degrade! Release into the blood instead! In adults contributes to the long half life of IgGs

Question 36

What does IgA look like?

Answer 36

monomer in serum | dimer in secretions

Question 37

IgM described as...

Answer 37

Low affinity, high avidity On subsequent Ag exposure, SAME IgM response, faster/better IgG response

Question 38

Which Ab help with ADCC?

Answer 38

A G E

Question 39

Which Ab fix complement?

Answer 39

A and G

Question 40

When you look for clonality, what are you looking for?

Answer 40

The exact VJD rearrangement | Rearrangement only occurs in B cells, not somatic cells