A3 antibody B cells Flashcards

B cells and antibodies

1
Q

key features of adaptive immune responses

A

specificity and diversity
-ensures response is targetted to relevent microbe
-can respond to variety of microbes
memory
-increased ability to combat infection by same microbe
clonal expression
-incrreases response to keep pace with microbe
specialisation
-generation of optimal type response
contraction and homoeostatis
-allows response to ‘reset’, no excessive inflammation
non reactivity to self
-prevents auntoimmunity

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2
Q

features of antibody

A

-variable region binds to specific antigen
-diff antibodies recognise/bind to different antigens or diff parts of antigens
-binding site is known as the epitope
-can be linear sequence or based on antigen folding

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3
Q

b cell generation

A

generated and selected in bone marrow
expresses b cell receptor BCR which recognises antigen
each BCR is different (adaptive)
recombination of genes similar to TCR

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4
Q

b cell variability

A

is associated with rearrangement of V-D-J regions of DNA
pre b cell randomly selects one of dozens of regions and links with other random units
generates variability within b cell population
-each b cell expressed different BCR

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5
Q

BCR structure and migration

A

structure is surface bound version of Ig
(when activated secretes antibody of same specificity)
once expressed functional BCR matures from bone marrow and enters periphery via lymph nodes

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6
Q

B cell activation

A

-recognition of antigen by bcr leads to activation of b cell and internalisation of antigen
-antigen broken down to peptides
-peptides loadedinto MHC II within b cell and presented to A.S CD4
-if t cell also recognises antigen it provides help (cytokines,costim)
-allows b cells to fully activate and secrete antibodies

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7
Q

b cell help

A

CD4 helper t cells help b cells via CD40
T cells influence antibody production through sytokines
induces proliferation of b cell and differentiation
-plasma cell
-memory cell

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8
Q

3 key functions of antibody

A

neutralisation
opsonisation
complement

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