Antibodies Flashcards
Where do B-cells originate from?
bone marrow
What are naive B-cells?
B-cells that have not met antigen and circulate from blood into peripheral lymphoid tissues, the main site of antigen encounter
What happens to germinal centres in the lymph nodes?
they grow, during immune response, due to cell proliferation
In the spleen, how do the antigens enter?
in the blood
Why is immune response greater and faster after initial exposure?
some B-cells don’t die and instead ‘turn off’ and become memory T-cells and lie dormant until needed
What are the key features of B-cells?
+ antigen specific
+ have a “memory”
What are the advantages of the B-cells secondary memory response?
+ faster
+ can produce more antibody
+ doesn’t prevent a response to another antigen
What are the separate functions of antibodies?
- to bind the pathogen that caused its production
2. recruit other cells and molecules that will lead to clearance/destruction of pathogen
What are the two parts that make up an antibody?
binding and activation parts
What is junctional diversity?
DNA sequence variations introduced by the improper joining of gene segments during the process of V(D)J recombination
Where does junctional diversity occur?
only in B-cells
What are the 4 ways antibody diversity is created?
- rearranging multiple gene segments
- junctional diversity
- different combinations of H and L chains
- somatic hypermutation
What is affinity maturation?
when cells with increased affinity for antigen during the course of an immune response are selected to expand and secrete antibody
What are the 5 classes of antibody?
\+ IgG \+ IgM \+ IgD \+ IgA \+ IgE
what type of multimer can IgM be secreted as?
pentamer - involves additional J chain
what type of multimer can IgA be secreted as?
dimer - involves additional J chain
what are the main Ab isotypes in plasma?
IgG and IgM
what are the main Ab isotypes in extracellular fluid?
IgG and monomeric IgA
where does dimeric IgA predominate?
secretions across epithelia, including breast milk
how does a foetus receive IgG?
transplacental transfer
where is IgE found mostly?
near to epithelial surfaces, especially gut, lungs and skin
what antibody does a foetus receive via transplacental transfer?
IgG
what is ADCC?
antibody-dependent cell-mediated cytotoxicity
what is a major cause of glomerulonephritis?
high levels of Ab-Ag complexes
