3. Antibody classes

Question 1

how many IgG subtypes?

Answer 1

4

Question 2

how many IgA subtypes?

Answer 2

2

Question 3

what type of molecules are Ab?

Answer 3

immunoglobulins, glycoproteins

Question 4

5 places you would find Ab

Answer 4

1. breast milk
2. blood
3. saliva
   4, tears
4. plasma

Question 5

which is the most abundant Ab in plasma?

Answer 5

IgG

Question 6

which Ab has longest half life?

Answer 6

IgG

Question 7

which Ab is predominant in secondary response?

Answer 7

IgG

Question 8

which Ab is used in vaccination?

Answer 8

IgG

Question 9

which Ig crosses the placenta?

Answer 9

IgG

Question 10

which disease can be caused by IgG? explain it

Answer 10

Haemolytic disease of newborn

1. 1st baby is rhesus +ve and mother is -ve
2. Baby Ag cross placenta
3. Mother creates Ab
4. in second preg - Ab cross placenta and kill baby

Question 11

Describe IgG structure

Answer 11

4 polypeptide chains ; 2 heavy and 2 light joined by disuphide bonds (3)
2 identical Fab regions (antigen binding) and 1 Fc region (Ab binding to receptor) (2)

Question 12

which Ab needs to be matched during blood transfusions?

Answer 12

IgG

Question 13

in the diffferent IgG subclasses- which part of the Ab differs? how does it differ?

Answer 13

Fc region - difference in AA

Question 14

All IgG subclasses can cross the placenta except?

Answer 14

IgG2

Question 15

State what each IgG subclass is produced in response to

Answer 15

IgG1 + 3 = T-cell dependent antigens (viral ag)
IgG2 = polysaccharide Ag
IgG4 = extracellular parasites

Question 16

which IgG subclasses are higher in childhood and which are higher in adulthood?

Answer 16

IgG1 + 3 = children

IgG2 = adult

Question 17

IgG can be measured to diagnose what disease?

Answer 17

autoimmune hepatitis

Question 18

IgG can be measured for check serological immunity (after vaccination) - for what 5 diseases?

Answer 18

MMR, Hep B, Varicella (chicken pox)

Question 19

which is the largest Ab?

Answer 19

IgM

Question 20

when is IgM produced?

Answer 20

primary response

Question 21

where is IgM found?

Answer 21

lymph nodes + secretions

Question 22

does IgM cross the placenta?

Answer 22

no

Question 23

what does IgM activate?

Answer 23

complement

Question 24

Describe structure of IgM (4)

Answer 24

1. pentamer (5 Ab)
2. joined by disulphide bonds and protein J chain
3. larger heavy chains
4. 10 epitopes - but only 5 bind due to size

Question 25

give 3 diseases where IgM is raised?

Answer 25

1. liver disease 2. myeloma 3. Waldenstrom's macroglobinanaemia

Question 26

give 3 times where IgM is low?

Answer 26

1. infancy 2. acquired deficiency 3. hereditary deficiency

Question 27

Describe haemolytic blood transfusion reaction

Answer 27

- when someone is not given their blood group in a transfusion - blood cells attack and cause destruction of incompatible blood

Question 28

what is mutliple myeloma?

Answer 28

cancer of plasma cells

Question 29

pathophysiology of mutliple myeloma

Answer 29

1. plasma cells produce paraprotein - Abnormal M protein | 2. Protein builds up in the blood, urine, bone marrow

Question 30

SXS of mutliple myeloma

Answer 30

no lump | prescence of paraprotein in blood/urine

Question 31

why does mutliple myeloma have its name?

Answer 31

it affects multiple places around the body - spine, skill, pelvis, rib cage, long bones

Question 32

What is waldenstrom's macroglobinanaemia ?

Answer 32

cancer of plasma cells - high levels of IgM

Question 33

where is IgA most prevalent?

Answer 33

secretions

Question 34

function of IgA

Answer 34

protect mucosal surface from infection

Question 35

most numerous IgA subtype?

Answer 35

IgA1

Question 36

describe structure of IgA subtypes

Answer 36

IgA1 = monomer IgA2 = dimer which is held together by disulphide bonds and J chain has additional secretory protein wrapped around Fc region

Question 37

where is IgA2 found?

Answer 37

saliva, tears, colostrum (breastmilk), mucus, sweat, glands, gastric fluid

Question 38

what cells produce IgA2?

Answer 38

epithelial

Question 39

which surfaces are protected by IgA2?

Answer 39

1. resp 2. GI 3. Genitourinary

Question 40

what is the most common Ig deficiency?

Answer 40

IgA

Question 41

what 3 diseases are IgA deficienct people prone to?

Answer 41

1. chest infection 2. coeliac disease 3. pernicious anaemia

Question 42

Least abundant and shortest half life Ab

Answer 42

IgE

Question 43

function of IgE

Answer 43

immunity to parasites + helminths

Question 44

Describe physiology of IgE

Answer 44

1. parasite/helminth invades 2. IgE attaches to receptors on basophils + mast cells 3. causes secretion of proteolytic enzymes, histamine + tryptase to kill pathogen

Question 45

when IgE binds to mast cells, it can cause Type 1 hypersensitivity. give 3 examples of this

Answer 45

1. allergic asthma 2. allergic rhinitis 3. food allergies

Question 46

name of syndrome where IgE is high

Answer 46

Job's syndrome

Question 47

SXS of Jobs syndrom

Answer 47

1. skin, resp + ear abscesses | 2. weak immune response

Question 48

cause of Job's syndrome

Answer 48

defect of STAT3 gene on chromosome 4

Question 49

which other Ab can bind to basophils and mast cells?

Answer 49

IgD

Question 50

where is IgD found?

Answer 50

membrane

Question 51

what is HIDS?

Answer 51

Hyper IgD syndrome

Question 52

SXS of HIDS (5)

Answer 52

1. skin rashes 2. fever 3. abdo pain 4. vomiting 5. sudden onset pyrexia

Question 53

cause of HIDS

Answer 53

mevalonate kinase gene mutation

Question 54

in class switch recombination, which region of the Ab changes?

Answer 54

constant

Question 55

how does CSR occur on a molecular level?

Answer 55

interchromosomal deletion, recombination

Question 56

In CSR: where does the DNA break?

Answer 56

switch region

Question 57

In CSR: where does substitution occur?

Answer 57

constant region

Question 58

In CSR: what causes free ends of DNA to join back together?

Answer 58

NHEJ - non-homologous end joining