Immunology 5 Flashcards
(14 cards)
B cells recognise __________ antigens through the ___ at the cell surface
unprocessed, BCR
what does B cell activation result in?
production of antibodies, plasma cells and memory cells, and defense against pathogens in the humors (fluids)
what is an antibody?
the secreted form of a B cell receptor
what are the two light chain isotypes for antibodies?
k and y
what are antibody isotypes important for?
working in different parts of the body and at different stages of the immune response
- IgM is first reponse AB
- IgG is neutralising
- IgA is bloodstream and mucosal
what is a polyclonal response?
when multiple different antibodies are produced against different antigens of the same pathogen
- common in viral infections
what are thymus independent antigens
lipid or polysaccharide molecule that binds to BCR and TLRs.
- no T cell help required, short lived response and no memory cell creation
true or false, B cells express MHC II
true
describe linked recognition
B cells are activated by helper T cells that recognise the SAME ANTIGEN (but it can be a different epitope)
describe B cell activation in the lymph node
naive T cell and naive B cell migrate to to the border of the B cell follicle and T cell zone via cytokines where linked recognition leads to B cell (and T cell) activation.
what happens to B cells after linked recognition/activation?
they can either differentiate into plasma cells (then to periphery) or move into the germinal centre in the B cell zone
what is the role of the germinal centres?
affinity maturation due to somatic hypermutation -> selection of B cells with higher affinity for their antigen
- or class switching (e.g from IgM to IgG)
what are the three main functions of antibodies?
neutralisation, complement activation and opsonisation
what is direct ELISA vs Indirect ELISA?
direct: uses only primary AB
indirect: also uses secondary AB
