B cells and Antibodies Flashcards Preview

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Flashcards in B cells and Antibodies Deck (71):
1

definition of antibodies (imunoglobulins)

proteins made and secreted to bind with antigens. Once bound, helps inactivate/clear out microbial (or non-microbial) agent

2

Ig structure

2 identical heavy chains and 2 identical light chains

3

light chains isotypes and their frequnecy

kappa (60%), lambda (40%)

4

heavy chain isotypes

α - IgA 1, 2
δ - IgD
γ - IgG 1, 2, 3, 4
ε - IgE
μ - IgM

5

FAB

fragment antigen binding: portion of antibody that binds antigen

6

FAB is produced by digestion of Ig with what enzyme?

Papain

7

Fc

Fragment crystallizable: effector function of Ig, binds with other things that have an Fc receptor

8

Fc contains which portion of the antibody molecule?

C-terminal portion

9

F(ab'2) and produced by which enzyme

Bivalent FAB fragment, produced by pepsin

10

Ig molecule consists of how many FAB and Fc fragments?

2 FAB and 1 Fc fragment

11

how many hypervariable regions (CDRs) are on each light and heavy chain? How many in total on an Ig?

3 on light chain, 3 on heavy chain, a total of six

12

Basis of specificity for antigen

HV regions = CDRs (complementarity determining regions)

13

What makes up one FAB region?

VL, VH
CL1 CH1

14

How many variable (heavy and light) domains are on an Ig?

On variable heavy, one variable light on each half of Ig, so in total, 2 VH and 2 VL

15

How many Constant light domains are on each Ig?

One CL on each side of Ig, so a total of 2 CL domains

16

How many constant heavy domains are there on each Ig? Which two Igs are an exception

3 constant heavy domains on each side, so 6 in total. IgM and IgE can have a fourth constant heavy domain

17

less variable regions aligning hypervariable regions that provide structural integrity to variable domains

framework residues

18

Isotype

constant regions of heavy/light chains

19

idiotype

antibodies with different variable domains

20

Igs that are complement activators

IgG and IgM

21

B-cell membrane receptors (mature cell)

IgM and IgD

22

First antibody during immune response

IgM

23

The only antibody produced by immature B-cell

IgM

24

2 fates of IgM and structural form for both

-plasma membrane bound, serves as B cell receptor for antigen or B cell activator (monomer)
-secreted from plasma, potent activator of compliment classical pathway (pentamer)

25

Second isotype of Ig produced

IgD

26

very similar to IgM but contains different Fc portion

IgD

27

the "glue" that hold a pentamer Ig together

J-chain

28

Ig with highest serum concentration

IgG

29

5 important properties of IgG

1) longest half life (much more stable, resists degradation) ~23 days
2) the only Ig that can cross placenta to provide fetus immunity
3) can perform ADCC
4) acts as an opsonin
5) compliment activator

30

In opsonization, what party of the antibody binds to the bacteria? what part of the antibody binds to the phagocyte?

FAB binds to antigen of bacteria, FC site binds to an Fc (gamma) receptor on on phagocyte

31

What receptor is needed for IgG to perform ADCC?

CD16

32

Why is IgG a less efficient compliment pathway activator than IgM?

IgM is secreted as a pentamer, while IgG is a monomer, so its needs multiple monomers

33

"Prepare to ingest"

Opsonin

34

Ig involved in mucosal immunity

IgA

35

IgA is secrete as what structure?

Dimer

36

Which antibody does not activate compliment pathway? Way?

IgA, dont' want a huge inflammatory response in GI tract

37

Mild, neutralizing antibody

IgA

38

This Ig is mostly found on epithelial cell surfaces and binds to bacterial toxin to prevent epithelial damage

IgA

39

least common Ig, small amounts in circulation

IgE

40

Ig for allergic reactions, hypersensitivity reactions, and parasitic infections

IgE

41

This Ig is mainly found in lungs, skin, and mucous membranes

IgE

42

Mast cells have these receptors fo IgE

Fc epsilon receptors

43

Crosslinking of antibodies and antigen on mast cell causes what to occur and what to be released?

Degranulation of mast cells, release of histamine
(binds to antigen first, then triggers opsonization)

44

mABs (3 properties)

monoclonal antibodies
1. targets only a single polypeptide chain
2. no variation between antibodies produced
3. highly controllable

45

Rituximab

mAB, marker on B cells, used in treatment of lymphoma and leukemia

46

Infliximab

Anti-TNF (tumor necrosis factors, cause apoptosis)
hence why need to be careful with monoclonal antibodies. need these things as inflammatory mediator

47

Monoclonal antibodies bind to the same _______ of antigen, which serves to detect and purify a substance

epitope

48

Monoclonal antibodies work only because B-cells operate through this type of system

Clonal selection
(each B-cell has a specific antibody as a cell surface receptor, and only B cells, which are antigen specific, can secrete antibodies. Produce antibody of a specific type which we can isolate and capture)

49

What type of interaction occurs between an antibody and antigen

noncovalent

50

Reaction between an antibody and an antigen that differs from the immunogen

Cross-reactivity

51

Type B blood type have what type of antigens

B antigens

52

Persons who are Type AB what what antigens

A and B antigens

53

What antigens to persons with Type O have

have neither A nor B antigens

54

The serum of people with Type A blood have what kind of antibodies

Antibodies against Type B antigens

55

Type AB blood type have what kind of antibodies

Neither antibody

56

Type O blood type have what antibodies

antibodies against A and B

57

Universal Donor

Type O

58

Universal recipients

Type AB (lack antibodies against A or B antigens

59

True or False: A person with type O blood may receive from a person with Type B blood

False (a person with type O blood has anti-B antibodies which would react against the type B antigen found on the red cells of type B blood

60

When Type B blood is given to a person with type A blood, antigen from the _____ reacts with anti-B antibody in the ____ (donor or recipient)

Donor, recipient

61

Blood group antigens are a system of antigens that are ____ in nature

glycolipid

62

What is the core glycan anchored in the erythrocyte membrane? Everyone has this, and will not react to this

Gal NAc--Gal--X
|
Fucose


Gal NAc =N-acetylated galactosamine
Gal= galactose
X= the R group that is different in each blood type

63

X group for O

nothing

Gal NAc--Gal
|
Fucose

64

X group for A

Gal NAc--Gal--GalNAc
|
Fucose

65

X group for B

Gal NAc--Gal--Gal
|
Fucose

66

immunogenicity

ability of a particular substance to induce an immune response (i.e. antigen or epitope)

67

What elicits the blood group antibody reaction?

GI flora (commensal bacteria) generate proteins/sugars/etc that are foreign to humans. Immunse system response to these antigens, but the bacteria never leave the GI tract. Bacteria are harmless within the GI lumen. But antibodies are ready in case any bacteria does cross epithelium

68

GI bacterial biproducts have structura similarity to

blood groups

69

True or false: Individuals do not make specific antibodies against bacteria in the gut that are similar to their own blood type

True. They do not.

70

Lipids and nucleic acids alone are (strong/weak) generators of antibodies

Weak. generate more robust response as lipoprotein or nucleoprotein, which will be processed by an APC

71

If a lipoprotein is degraded by APC, which part does Th cell recognize? Which part does B cell recognize? (but relies on Th still)

Helper T cell recognizes the peptide. The B cell can recognize the lipid or carb part, but need Th cell from protein to help it recognize the lipid or carb.