what’re epitopes
the site of antigen that’s recognised by lymphocyte receptors
what type of cell is more likely to recognise linear epitopes
t-cells
what type of cell is more likely to recognise discontinuous epitopes
b-cells
why are antibodies bifunctional
- recognises & binds to antigen
- recruit other elements of the immune system
which terminal of the antibody bind to:
- self cells
- antigens
- C terminal
- n terminal
what happens if papain digests antibodies
- cuts of top above S-S
- forms 2xFab + 1c Fc
what happens if pepsin digests antibodies
- cuts off bottom below S-S
- 1xF(ab’)2
what’s the makeup of the light chain and the heavy chain in IgG
(structure)
light chain = 2x Ig folds
heavy chain = 4x Ig folds
what’s the function of an Ig determined by
the Fc regions
what’re the 4 functions Ig classes
- neutralisation
- opsonisation
- activate complement system
- intracellular (binds to Virus and enters cell to kill)
normally IgV and IgC regions/domains are separate, how come they can rearrange in B-cells
IgV and IgC are close together
what’re the 3 ways to establish gene diversity in somatic recombination
germline diversity
combinatorial diversity
junctional diversity
what’s germline diversity
many choices of gene segments (initial diversity present in the DNA)
what’s combinatory diversity
random segments brought in random orders
what’s junctional diversity
joining of different gene segments together
what does RSS do
-RSS serves as recognition sites for the RAG proteins
- involved in 12/23
- recognition and cleavage
what adds N nucleotides
TdT
what’s the immunoglobulin structure:
- IgD
- IgG
- IgA
- IgM
- IgE
- IgD x2
- IgG x2
- IgA x2
- IgM x10
- IgE x2
what’s the function of RAG in context of junctional diversity
cleaves/reorganises DNA & + P nucleotides
what’s needed for somatic recombination of light chain
V regions = 2xV + 1xJ
1x somatic recombination
removing introns splicing
whats needed for somatic recombination of heavy chains
V regions = V, D, J
splicing
2x somatic recombination
SCID
- what causes it
- what does it cause
mutations in RAG1 & 2
cause recombination deficiencies
