Humoral Immunity Flashcards Preview

Foundations Test 4 > Humoral Immunity > Flashcards

Flashcards in Humoral Immunity Deck (73):
1

FAB

Made of Vl and Vh regions...binds the antigen

2

FC

Constant region that determines function and binds to macrophages, T cells, etc.

3

Antibody hinge region and how is entire thing held together

Allows flexibility

Disulfide bonds

4

How many HV regions per chain

3

5

AB vs. T cell antigen binding

AB can bind tons of stuff

T cell only proteins

6

Other region besdies HV

Framework...pretty stable

7

Antigen binding sites composed of

HV regons

8

AB:antigen interaction due to

Noncovalent forces...means it is reversible

9

Which region only in heavy chain?

Diversity region

10

Which region has most functional gene segments?

Variable

11

Combinatorial diversity

Random joining of D/J regions (example)...other regions can be brought together as well

12

Junctional diversity and how it happens

RSS brings together junctions...RAG 1 and 2 generate hairpins at region...TdT adds N-nucleotide additions and alters

13

In absence of TdT

Still some antibodies but lack diversity

14

Absence of Rag 1 and 2

No recombination...therefore no B cell formation
Cause of SCID

15

Allelic exclusion of AB

Only one copy of Ig genes are expressed on an individual cell

A heterozygous Ig will only display one specificity on its surface

16

Alleles for each type of AB

M - M
G - G1-4
D - D
E - E
A - A 1-2

17

Which activate complement via classical pathway?

IgG1 -3
IgM

Bind to C1q

18

Whcih transfer placental

IgG

19

Which bind to marcophage Fc receptors

All but IgM, IgD, and IgG2

20

Which bind mast and basophils

IgE

21

Which are reactive with Staph protein A

IgG

22

Amount of Igs in serum

IgG in serum is most
IgM and IgA present
IgD not in serum
Small IgE

23

Weird structures of Igs and consequences

Dimeric IgA - 4 binding sites
Pentameric IgM - 10 binding sites

Increases avidity - binding of entire molecule

24

2 types of determinants

Conformational - need geometry in order to recognize
Linear determinant - may not be able to bind if there is geometry

25

B cell developmet

Stromal cells aid in development
Go through negative selection in the bone marrow (if bind to self, will try to rearrange and if not, then killing)
Activated outside of bone marrow by lymphoid organs by meeting foreign antigen
Give rise to memory and plasma cells in bone marrow and lymphoid tissue

26

When B cells first secreted, only have

IgM and IgD

27

Important IL for B cell development

IL-7 - uses common gamma chain - deficiency leads to SCID

28

Which chain develops first

Heavy chain...will have IgM before IgD

29

BK

Bruton's tyrosine kinase
Deficiency leads to B cell deficiency

30

IL-7R

Important in expansion of B cells

31

Arrangement of heavy chain

D-J first
then V-DJ

32

L-chain arragnement

V-J rearranged

33

Receptor editing of B cells

If expression in mu chain is to self, will undergo rearrangement of light chain to try to eliminate this effect...if still bind to self, apoptosis

34

If B cell self-binds to soluble self molecule in bone marrow

Anergic B cell migrates to peripher y

35

If B-cell binds very low affinity self molecule in bone marrow

Clonally ignorant cell migrates to periphery...could still be activated

36

In spleen, if B cell recognizes self

Same things as in bone marrow

Will eventually mature if low-affinity (clonal ignorant) or no reaction (mature)

37

3 things AB does

Neutralization
Opsonization
Complement Activation

38

Thymus-dependent B cell stimualtion

BCR binds antigen and stimulates signaling...antigen taken in with BCR and processed into class 2 MHC...presented to T cell along with CD40 which binds CD40L...causes class switching from IgM to another type

39

CD40/CD40L defieincy

Hyper IgM...can't class switch...susceptible to pyogenic bacteria

40

T-independent stimulation

2 options

Polyvalent antigen cross linking AB binds...no class switching

TLR binds a mitogen - no class switching

41

Polysaccharide activation

Is T-independent (no IgG and no memory)...by attaching a protein to the polysaccharide, you can generate memory (IgG)

Hib/pneumococcal conjugate vaccines

42

Tfh cells

T follicular helper cells
Bind to B cell using CD40L/CD40 interaction and allow proliferation of B cells by producing cytokines

43

Difference between B and T cell viral activation

T cells recognize things on the inside
B cells recognize surface of virus

T cells can help B cells recognize linked epitopes even if not identical

44

How do antigens get into lymph node

Via dendritic cells via affarent lymphatics

45

B cells enter lymph nodes through

HEVs and move through follicles to germinal centers

46

FDCs have what receptors?

Fc and complement receptors
FcR and Cr1

47

PLasma cells wil migrate to

Bone marrow

48

2 things that happen during maturation of AB response and where does it happen?

Somatic hypermutation - mutated genes and expresson of different AA allows variability
Class switch - changes function

Germinal centers

49

IFN-gamma = which Ig and function?

IgG - opson, complement, placental

50

IL-4 = which IG and function/

IgE, IgG4 - helminths protection and mast cell degranulation

51

TGF-B, APRIL, BAFF = which Ig and function?

IgA...mucosal immunity in lungs and gut

52

Class switching

Nothing changes except for constant region

Requires AID

53

Somatic hypermutation

Select high-affinity antibodies that change affinity (not specificity)

Requires AID

54

As number of responses increases

Number of somatic hypermutations increases as well to select for best antibody

55

If AID is lost then,

Lower affinity B cells with mostly IgM antibodies

56

IgA function

Secreted into the lumen via pIgR receptor...binds to toxins and pathogens...opsonization for destrution

57

Distribution of AB through body

IgG and IgM in blood
Dimeric IgA at mucosal
IgE - around the skin ...passed to child

58

Antibody toxin neutralization

Prevents binding of toxin to cell

59

Antibody virus neutralization

Blocks virus bindign to cell membrane

60

Antibody bacteria neutralizatio

Block to adhesins of bacteria and prevent association with cell membrane...also complement

61

Antibody - complement

IgM and IgG bind to and activate C1q

62

Antibody immune complexes

Get cross linking of antibodies and activate complement...C3b binds to pathogen as well...complement receptor CR1 on erythrocytes binds via C3b...takes ot spleen and liver where phagocytic cells destory

63

Free Ig will not

Cross-link Fc receptors on macrophages...need to be bound to bacterial surface

64

Eosinophils attack

IgG and IgA coated schistosome larva

65

ADCC

AB binds on target...NK cell recognizes and induces apoptosis

66

Mast cell degranulation

Via IgE...cross-links

67

In secondayr response, what is differnet?

IgA and IgG more than IgM...high affinity, high somatic hypermutation

68

If you see more IgM

Then probably early in process and maybe the first time infected

69

If mostly IgG,

Pathogen is gone or this is not the first time they have seen ti

70

CD40/CD40L def

CD40L (x-linked)

Hyper IgM

71

AID def

Hyper IgM

72

BAFF and APRIL def

No differentiation into Igs in the spleen

73

TACI def

common variable immunodeficiency