Antibody biology Flashcards
which response do B cells activate
humoral response, responsible for producing antibodies.
where do b cells originate and mature
bone marrow
what happens to the B cells upon activation with antigens
they differentiate into plasma cells which are antibody-producing factories
what do plasma cells secrete
antibody of the same specificity as the membrane-bound immunoglobulin expressed by their B cell precursor
FAB
fragment antigen binding - responsible for binding antigen
FC
fragment crystallisable - responsible for effector function
what does the flexible hinge of IgG allow
allows for both arms to bind to many arrangements of antigens on pathogen surfaces
what are the two types of light chains
Lambda and Kappa
In any individual antibody molecule, are the chains the same or different
both light chains
which chain determines the class of antibodies
heavy chain
what do antibodies fold into
globular domains with distinctive 3d structure
what do the globular domains comprise of
2 beta sheets with a total of 7 or 8 antiparallel beta strands which are linked by disulphide bridge to form a beta parallel.
this folded structure is known as the “immunoglobulin fold”
what do hypervariable loops form
antigen binding site
what are hypervariable loops known as
complementarity-determining regions (CDRs)
what happens when VH (variable heavy) and VL (variable light) domains are paired
their 6 CDRs creae the antigen-binding site
what is an epitope
An epitope, also known as an antigenic determinant, is the specific region on an antigen that is recognized and bound by an antibody, a B cell receptor, or a T cell receptor.
what is a linear epitope
epitopes in protein antigens may comprise a single stretch of polypeptide chain
what is a discontinuous epitope
3D folded like structure where the polypeptide chain is not continuous
what can epitopes bind to
pockets, grooves, extended surfaces or projections in antigen binding sites
each individual has an antibody repertoire (available antigen specificities) of approximately how many
1011
epitopes for antibodies are exposed where
on pathogen surfaces
how is the antibody repertoire achieved
Ig genes are organised differently to other genes, in all cells except B cells, Ig genes are in fragmented form that cannot be expressed
Ig heavy and light chain loci consist of families of gene segments, arrayed sequentially along the chromosome
* They are inherited in this form through egg and sperm (germline)Therefore their arrangement is termed “germline configuration”
* In developing B cells, Ig gene segments must be rearranged to assemble functional light and heavy chain gene
VH domain is encoded by what
V (encodes most of the V domain) ,D (diversity segment) and J (Joining segment) gene segments
VL domain is encoded by what
V (encodes most of the V domain) and J (Joining segment) gene segments
