B cell development 3 Flashcards
How good are the B cell receptors at recognising an antigen?
Badly–> they bind poorly to it–> low affinity
What do activated b cells that dont proliferate or turn into memory cells to?
Migrate to a germinal centre
What happens to b cells in the germinal centre?
They start to divide
What does cytodine deaminase do to B cells?
Introduces somatic mutations in immunoglobulin coding genes
What is somatic hypermutation?
B cells mutating in many different ways while proliferating in germinal centres
Benefit of somatic hypermutation?
Might cause a B cell with higher antigen affinity to form
How do the B cells with higher affinity formed as a result of somatic hypermutation proliferate the most?
They are more likely to bing to t cells, more likely to get a cognate interaction and so more likely to get proliferation signals from t cells
Difference in affinity between plasma cells produces at the start vs end of an immune response?
Plasma cells at the end have a higher affinity than the ones at the start
What is affinity maturation?
Only the b cells that have the highest affinity for the antigens will mature further and proliferate
How do autoimmune diseases occur?
Breakdown of tolerance mechanisms
Does class switching change the antigen binding specificity?
no
What does class switching change?
The type of heavy chain produced
Which immunoglobulin can cross epithelial barriers?
IgA
Why can IgA cross epithelial barriers?
Epithelial cells have receptors on their surface that bind to IgA and transport it via transcytosis
Functions antibodies can carry out?
Neutralisation, opsonisaiton, signalling for phagocytosis
