adaptive immunity Flashcards

1
Q

3 general characteristics of an adaptive immune response

A

it takes time to generate, it is highly specific, and it has memory. (unlike the innate response)

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2
Q

where does BCR rearrangement occur

A

in the bone marrow

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3
Q

what secretes antibody

A

plasma cells

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4
Q

what are epitopes

A

the antigenic determinants. the small parts of molecules that antibodies interact with.

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5
Q

what are linear epitopes

A

where the epitope interacted with is a sequence of consecutive amino acids.

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6
Q

epitopes other than linear ones?

A

conformational epitopes. the epitope interacted with when a protein enters its native 3D structure.

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7
Q

what does the variable region of the AB do

A

interacts with the antigen

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8
Q

what does the constant region of the AB do?

A

recruits effector funcitons. eg via FcR on macro, neutro, baso and mast cells. or with complement.

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9
Q

what’s the primary response in the infection

A

the first encounter with an antigen generates the primary response.

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10
Q

difference with an immunological secondar response vs primary response

A

its more rapid and generates more antibody

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11
Q

3 MOA of antibodies

A

1 - neutralisation - block biological activity
2 - opsonisation - FcRs for phagocytosis
3 - complement activation - can cause lysis or opsonisation

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12
Q

where do T cells arise

A

they arise in the bone marrow but mature in the thymus - where the TCR genes rearrange

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13
Q

what does the TCR recognise

A

only degraded protein fragments when complexed with MHC. antigen processing generates the peptides for display on the antigen presenting cells

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14
Q

origin of peptides for MHC class1

A

the cytosol

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15
Q

cytotoxic T cells?

A

important for killing virally infected or tumour cells.

  • MHC class 1 restricted
  • CD8 coreceptor
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16
Q

t helper cells

A

MHC class 2 restricted

  • express the CD4 coreceptor
  • provide help for B cells and cytotoxic T cells.
  • class 2 predominantly found on APCs
17
Q

whats a primary/central lymphoid organ?

A

the thymus and the bone marrow

18
Q

what are mature/naive t/b cells?

A

those that have rearranged their receptor but are yet to be exposed the their antigen

19
Q

what activates naive t cells?

A

professional APCs

20
Q

what do naive lymphocytes do once released into the circulation

A

assume a role of patrol and respond.

21
Q

the degree of the patrol and respond behaviour

A

2.5x10^10 lymphocytes pass through a lymph node each day, 1-2% of the pool recirculates each hour.
this massive rate of circulation ensures that the lymphocytes with receptors of the correct specificity will come into contact with the antigen if it is present.

22
Q

what are the lymph nodes and the spleen examples of and what do they both do

A

they are secondary/peripheral lymphoid organs and they optimise the interaction between the APC and T and B cells.

23
Q

how does the lymphatic system prevent pathogens getting into the blood

A

the lymphatics are lined with macrophages to catch them

24
Q

how do lymphocytes get into the lymphatic nodes

A

through high endothelial venules

25
Q

what happens when a dendritic cell enters a lymphoid organ

A

it enters the T cell area where naive T cells survey the antigen it is presenting on its MHC, the T cells that recognise the antigen/MHC are retained and are stimulated to differentiate into effector T cells.

26
Q

what happens when naive B cells enter a lymph node

A

if they have a receptor specific for a presented antigen then they recieve help from activated effector T cells and are stim to produce antibody. so B cells concentrate in B cell areas around follicular dendritic cells

27
Q

what are follicular dendritic cells

A

FDCs - use receptors for Ig or complement to hold bound antigens on their surface (unprocessed) for a long period of time so that it can be screened by B cells.

28
Q

whats affinity maturation

A

the process by which cells with the highest affinity for an antigen are preferentially induced to proliferate.