B cell immunity - part 2 Flashcards
What B cells initiate the secondary immune response?
Memory B cells
Do we still need a Tfh cell for the secondary response?
Yes
Memory responses are more protective as _____ B cells respond to protein antigen, leading to _____ Abs produced.
more
more
The memory responses produce more of what?
More long-lived plasma cells and more memory B cels
What are differences between the primary B cell response, and subsequent ones?
Primary response takes longer to initiate.
Primary response secretes IgM first, then other antibody types later; secondary response has an increased number of IgG, IgA and IgE earlier.
Secondary response is stronger than the primary response
What are non-protein antigens that B cells can bind to?
Lipids and polysaccharides
When B cells bind to non-protein antigens, what cell types are produced by clonal expansion?
short-lived plasma cells only
What is a major difference between B cells responding to protein antigens, and responding to non-protein antigens?
No Tfh cell input is needed when responding to non-protein antigens
Why are Tfh cells not needed when a B cell responds to a non-protein antigen?
Non-protein antigens have very high affinity for BCR
What are the only antibodies produced when responding to non-protein antigens?
IgM
What is a major downfall of the response to non-protein antigens?
No long term memory
IgD:
- levels in the blood?
Function?
Where are most of them found?
Low levels in blood
Ab function is unknown/ bind pathogens as BCR
Most remain bound to naive B cells
IgM:
- location?
- Key characteristic?
Main form?
Mainly found in blood
First antibody produced in primary immune response
Pentameric
Which antibody type is the first one produced in newborns?
IgM
IgA:
- most abundant where?
- what does it provide to a newborn? How is this accomplished?
Most abundant Ab in secretions (mucus, tears, saliva, breast milk)
Provides passive immunity to newborn; maternal IgA transferred to newborn via breast milk
