Adaptive Immunity Flashcards

0
Q

Name the 2 secondary lymphoid organs

A

Lymph nodes

MALTs (mucosa associated lymphoid tissue)

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1
Q

What are the primary lymphoid nodes?

A

Bone marrow
Thymus
Spleen

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2
Q

What is the molecular structure of antibodies? (3)

A

Glycoproteins
2 light chains
2 heavy chains

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3
Q

What characterises a FAB fragment?

A

Vary in structure and antigen binding properties

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4
Q

What characterises a FC fragment? (3)

A

No antigen binding activity
Can bind to phagocytic cells
Can activate the compliment

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5
Q

What do B cell receptors induce? (5)

A
Signalling cascade:
Enhanced survival
Proliferation
Differentiation
Antibody secretion
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6
Q

What are the 3 regions of T cell receptors and what is the purpose? (4)

A

Variable
Constant
Membrane anchoring
Recognises only MHC class molecules

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7
Q

What is immunoglobulin repertoire?

A

Total number of antibody specificities a individual can create
~100 billion

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8
Q

What is the benefits of adaptive immunity?

A

Immunological memory, faster response

Clonal selection

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9
Q

What are the 4 sources of BCR (B cell receptors) variation?

A

Combinatorial V-D-J joining
Junctional diversity (addition or deletion of bases)
Somatic hypermutation
Variable combinations of H and L chains

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10
Q

How many recombinant variations does V-D-J recombination provide alone?

A

~2m

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11
Q

What is a V-D-J recombination?

A

A change in the DNA sequence of a immature B cells

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12
Q

What is needed to cause a change in the L chain of a immunoglobulin?

A

A recombination that combines a random V and a random J segment

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13
Q

What 2 changes is needed to cause a H chain variation?

A

1 random D and 1 random J

1random V segment and the combined DJ segment

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14
Q

When does somatic hypermutation occur?

A

Occurs in rapidly proliferating B lymphocytes

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15
Q

What are the 5 antibody classes?

A

Monomer
Dimers
Pentamers

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16
Q

What antibody class are IgG, IgD and IgE antibodies?

A

Monomers

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17
Q

What antibody class are IgM antibodies?

A

Pentamers

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18
Q

What antibody class are IgA antibodies?

A

Monomers or dimers

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19
Q

What does Ig stand for? (Eg. IgA)

A

Immunoglobulin

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20
Q

What are the functions of Ig A,D and E

A

A: protects mucosal membranes
B: main B cell regulator
E: defends against parasites

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21
Q

What are the functions of IgG and M?

A

G: neutralises viruses, activates compliment and helps ADCC
M: 1st antibody produced

22
Q

What is an antigen?

A

A molecule reacts specifically with an antibody

23
Q

What is the part of the antigen that is bound by the antibody?

A

Epitope

24
Q

What are CD4 cells?

A

T helper cells

25
Q

Where do T cells get created?

A

Bone marrow

26
Q

Where do T cells mature?

A

Thymus

27
Q

What do B cells do that T cells do not?

A

Secrete antibodies

28
Q

What do Cd4 co receptors bind to?

A

MHC class II molecules

29
Q

What do CD8 co receptors bind to?

A

MHC class II molecules

30
Q

What is the order of chain restructuring?

A

H chain first then L chain

31
Q

What does the enzyme activation induced cytidine deaminase do?

A

Causes a high rate of point mutations on the VDJ and VJ variable regions

32
Q

What is the initial assembly of the H chain?

A

IgM

Contains 10 binding sites though limited effector mechanisms

33
Q

What are the consequences of adaptive immunity?

A

Faster immunilogical memory
Clonal selection makes t and B cells makes a better response
Possibility of autoimmune disease

34
Q

What is humoral immunity?

A

Antibody mediated immune response

35
Q

What are the functions of the cell mediated adaptive immune response?

A

Cell mediated cytotoxicity via cytotoxic T cells (T cytotoxic)
Activation of phagocytes via T helper
Activation of B cells via T helper

36
Q

What are the similarities between B and T cells?

A

Appearance
Bone marrow origin
Diverse
Undergo clonal expansion after activation

37
Q

What is CD8 T cells mechanism of action?

A

Recognise antigens on MHC I
Activate
Destroy via cytotoxicity

38
Q

What is CD4 T cells mechanism of action?

A

Recognise antigens on MHC II
activate
Secrete molecules to activate CD8 and B cells

39
Q

What is the mechanism of T cell activation (3)

A

Interaction and co stimulation
Signalling cascade
Proliferation and differentiation of T cells

40
Q

What molecules do APC display?

A

MHC I and II molecules

41
Q

What does the activation of T cells cause?

A

Causes expression of IL-2 and IL2 on the activated cell (autocrine function)
Proliferates into effector cells (short lived)

42
Q

What do the IL2 secretions cause?

A

Activation of macrophages
Activation of T cytotoxic cells
Activate B cells

43
Q

What Is the role of of CD4 (T helper 2) cells

A

Control parasitic infections by:
Activates eosinophils and mast cells
Switches on B cells to produce IgE antibodies

44
Q

What Is the role of of CD4 (T helper 17 and F) cells

A

T17: stimulate neutrophils
Tf: stimulate B cells to produce antibodies

45
Q

What are the 2 mechanisms of CD8 activation?

A

By mature dendritic cells

With help of CD4 cells

46
Q

What is the mechanism of CD8 activation via dendritic cells?

A

MHC I activates IL2 receptors

Proliferation

47
Q

What is the mechanism of CD8 activation via CD4 antibodies?

A

Cd4 secretes IL2
Increase in B7 molecules
Activates CD8

48
Q

What is the role of CD8 cells?

A

Kill infected target cells with viruses via apoptosis

49
Q

What is the mechanism of action of fast independent cytotoxicity?

A

Recognition and attachment of NK cell to target
Release perforin/granzymes into interstitial space (membrane attack)
NK cell dissociation
Target cell destruction by apoptosis

50
Q

What is the mechanism of action of fas dependent cytotoxicity?

A

Proteolytic cascade in cytosol (caspases)
Disruption in mitochondria
Fragmentation of DNA

51
Q

What is the purpose of the humoral immune response?

A

Protects against extracellular pathogens

Prevents spread of intracellular infections

52
Q

How is the humoral response initiated?

A

Mainly via CD4

Directly by bacterial antigens

53
Q

What are the 5 main functions of antibodies?

A

Neutralisation of pathogens and toxins (not directly kill)
Opsonisation of bacteria and viruses (phagocytic facilitation)
Classic complement activation
Activation of NK cells
Degranulation of mast cells and basophils