Introduction to B cells and Antibodies

Question 1

What is IgD?

Answer 1

Antigen receptor virgin B cells

Question 2

What is IgM?

Answer 2

Agglutinin - activates complement

Question 3

What is IgG?

Answer 3

Opsonin - activates complement

Question 4

What is IgA?

Answer 4

Secretory - protects mucosa

Question 5

What is IgE?

Answer 5

Protection vs helminths

Question 6

List some Complements?

Answer 6

Cytolysis, Chemotaxis, Inflammation, Oposonisation

Question 7

Where are B cells?

Answer 7

Stay in lymph tissue and respond to antigens by differentiating into plasma cells

Question 8

How are B cells activated?

Answer 8

B cell receptors binding to specific antigents

Question 9

What do B cells in lymph tissue respond to?

Answer 9

Unprocessed antigents or antigens presented

Question 10

How do B cells secrete antibodie?

Answer 10

Once activated enlarge and differentiate into plasma cells

Question 11

What are antibodies?

Answer 11

4 polypeptide chains, 2 identical heavy and 2 identical light

Question 12

What are Heavy AA chains made up on?

Answer 12

450 AA

Question 13

What are light chains made up of?

Answer 13

220 AA

Question 14

How is light chain bound to a heavy chain?

Answer 14

By a disulphide bond

Question 15

How are 2 heavy chains held together at mid-region?

Answer 15

2 disullphide bonds forms hinge region

Question 16

What regions do both light and heavy chains posses?

Answer 16

V and C regions

Variable , constant

Question 17

What is the Variable region?

Answer 17

Confer specificity of antibody, found at tips of H and I chains on antibody arms

Question 18

What is Constant region?

Answer 18

Same in different antibodies and consist of H and L chains not associated with antigen binding

Question 19

What does Binding of antigen binding site with antigen cause?

Answer 19

Neutralization, Agglutination, Precipitation

Question 20

What is Neutralization?

Answer 20

Antibody covers bio active part of microbe

Question 21

What is Agglutination?

Answer 21

Antibody cross links forming a clump

Question 22

What is Precipitation?

Answer 22

Antibody cross links forming insoluble antigen antibody complex

Question 23

Exposed FC portion following antigen binding promotes what?

Answer 23

Complement fixation, Opsonisation, Activation of NK cells

Question 24

What is complement fixation?

Answer 24

FC of antibody complement protein activates

Question 25

What is Opsonization?

Answer 25

FC region of antibody binds to receptors of phagocytic cells

Question 26

What is activation of NK cells?

Answer 26

FC region binds to NK cells trigger TC chemical

Question 27

What is a Complement?

Answer 27

Complex system of number of serum proteins act in a sequence in humoral defence against extracell microorgs

Question 28

What are complement proteins?

Answer 28

C1-9

Question 29

What are Complement factors?

Answer 29

D,B,Properdie

Question 30

What are Complement receptors?

Answer 30

C1-3 - control proteins

Question 31

What does Antibody bind to? IGM/IGG?

Answer 31

Epitopes of antigen

Question 32

What does C1 bind to?

Answer 32

Fc region of antibodies

Question 33

What does C1r activate?

Answer 33

C1s which is proteinase

Question 34

What does C1s cleave?

Answer 34

C4

Question 35

What does C4b bind to?

Answer 35

Antigen whilst C4a stays in fluid

Question 36

What does C1 cleave?

Answer 36

C2

Question 37

What does C2b bid to?

Answer 37

Antigen and c2a in fluid

Question 38

What is C2b?

Answer 38

Proteinase cleaves C3

Question 39

What does C3b bind to?

Answer 39

Antigen and c3a in fluid

Question 40

What does c2b cleave?

Answer 40

C5

Question 41

What happens to C5?

Answer 41

Doesnt bind, c5a in fluid

Question 42

What does C5b bind?

Answer 42

C678 in fluid

Question 43

What does C5b678 bind to?

Answer 43

Lipid bilayer

Question 44

What does C9 do?

Answer 44

Inserts hole into membrane

Question 45

What is microorg lysed by?

Answer 45

Membrane attack complex

Question 46

Why are MACS deposited into bilayer of antigens?

Answer 46

Complement is enzymatic and cleave its substrate

Question 47

What is an e.g of MAC?

Answer 47

E.coli

Question 48

What does MAC do?

Answer 48

Form pores in lipid bilayer to kill gram negative bacteria

Question 49

What happens to gram positive bacteria in MAC?

Answer 49

Protect themselves from complement mediated lysis by thick peptidoglycan wall

Question 50

How do Funghi protect from MAC?

Answer 50

From complement mediated lysis by thick chitin cell walls

Question 51

Where does Gram positive pathway end?

Answer 51

C5 cleavage

Question 52

What are C3a and C5a?

Answer 52

Anaphylatoxins - activate mast cells | Chemotaxins - attract phagocytes

Question 53

What is C3b?

Answer 53

Opsonin - enables phagocytes to recognise and bind to antigens

Question 54

What is the alternative pathway?

Answer 54

Innate immunity with factors B,D,P activating enzymes

Question 55

What is hyperacute rejection mediated by?

Answer 55

Naturally occuring antibodies to a-Gal

Question 56

What is a-Gal?

Answer 56

Synthesised by a1,3Galactosyltransferase

Question 57

What do humans express a-Gal as?

Answer 57

Foreign and it is an epitope and have high titres of antibodies in gut

Question 58

Why are organs rejected?

Answer 58

Antibodies enter donor blood vessels and bind to a-Gal epitopes on endothelial cells, activating complement and neutrophils attracted, thromus blocks vessels, organ has no o2 and dies

Question 59

What is hyper acute?

Answer 59

Preformed antibodies to Gal-a1 and Gal epitope

Question 60

What is acute?

Answer 60

Direct pathway of immune recognition incompatible MHC II | Indirect pathway incompatible MHC I

Question 61

What is the antibody titre?

Answer 61

measureof immunological memory

Question 62

What is initial contact with antigen called?

Answer 62

Primary response

Question 63

What is a second encounter with same antigen called?

Answer 63

Secondary response producing vast amount of IgG antibodies

Question 64

Why does Age affect immunity?

Answer 64

Low levels of immune function, T cells less responsive to antigents