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Flashcards in adaptive immunity Deck (28):

3 general characteristics of an adaptive immune response

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


where does BCR rearrangement occur

in the bone marrow


what secretes antibody

plasma cells


what are epitopes

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


what are linear epitopes

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


epitopes other than linear ones?

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


what does the variable region of the AB do

interacts with the antigen


what does the constant region of the AB do?

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


what's the primary response in the infection

the first encounter with an antigen generates the primary response.


difference with an immunological secondar response vs primary response

its more rapid and generates more antibody


3 MOA of antibodies

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


where do T cells arise

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


what does the TCR recognise

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


origin of peptides for MHC class1

the cytosol


cytotoxic T cells?

important for killing virally infected or tumour cells.
- MHC class 1 restricted
-CD8 coreceptor


t helper cells

MHC class 2 restricted
- express the CD4 coreceptor
- provide help for B cells and cytotoxic T cells.
- class 2 predominantly found on APCs


whats a primary/central lymphoid organ?

the thymus and the bone marrow


what are mature/naive t/b cells?

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


what activates naive t cells?

professional APCs


what do naive lymphocytes do once released into the circulation

assume a role of patrol and respond.


the degree of the patrol and respond behaviour

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.


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

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


how does the lymphatic system prevent pathogens getting into the blood

the lymphatics are lined with macrophages to catch them


how do lymphocytes get into the lymphatic nodes

through high endothelial venules


what happens when a dendritic cell enters a lymphoid organ

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.


what happens when naive B cells enter a lymph node

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


what are follicular dendritic cells

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.


whats affinity maturation

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