B cells Flashcards
b cells generally (11 cards)
B1 B cells properties
- different progenitors compared to B2
- recognize capsular polysaccharide antigens
- produce IgM without T cells
- short lived don’t rely on BAFF
- provide early protection in life !!
B2 B cell properties
3 types: marginal, follicular, and memory
Marginal zone B cell properties
- rapid response to blood-borne antigens
- don’t need T cell help
- broad specificity
Memory B cell properties
- forms primary response (to re-incounters)
- not terminally differentiated, can undergo somatic hypermutation & class switching
Follicular B cell properties
- literally any b cell in a follicle.
- express both IgM & IgD
- high activation threshold (capable of big response)
What is the difference between long-lived plasma cells and Memory B cells?
LLPC are terminally differentiated (highly specific) B cells which reside in the bone marrow constantly producing antibodies.
If antigen mutates its GG
BUT… Memory B cells can continue to differentiate and adapt to them
B cell antibodies response to native proteins, what does this mean?
native protein = unprocessed whole protein
Describe properties of T cell independent B cell activation
- requires highly repetitive molecules (polysaccharides) which can trigger cross-linking
- usually limited to only IgM
- can also be activated by TLR dimerisation
Describe properties of T cell dependent B cell activation
- requires CD40 / CD40L interaction
- requires MHC2-antigen to TCR interaction
- additional cytokine signaling (IDK FOR WHAT PURPOSE)
Describe the ‘linked recognition of B cell responses’
DCs present peptide on MHC2 to naive CD4 T cells activating them against that peptide
B cells engulf the antigen drained to them via lymphatics, process it, become activated and present it on MHC2
T cell recognises same MHC2-peptide complex on B cell and fully activates it.
