Immunology Flashcards
antigenic epitope
part of pathogen that the surface immunoglobulin binds to
antigen binding specificity
antigens from one disease don’t work for all disesaase
antigens
anything that can be bound by immunoglobulins, but don’t produce an antibody
immunogens
subset of antigens that bind to Ig with the result of production of antibody
T or F all immuogens are antigens but not all antigens are immunogens
true
what factors influence immunogencity
foreignness (how different it is from human genome), size (how large?), structural diversity (lots of branching?) , chemical composition - is it a protein? carbohydrate, fatty acid? nucleic acid?
two light chains
lambda, kappa
in any one antibody
either two lambda or 2 kappa.. for short chains
IgG
2 gamma chains
IgA
2 alpha chains
IgM
2 mu chains
IgD
2 delta chains
IgE
2 epsilon chains
IgA,G,M,D andE held together by which type of bonds
are heavy chain types, disulfide bonds
Fc region
biological activity or effector region, receptors of immune system bind to effect some function of immunity
Fc region
more constant than highly variable region of Fab
N-termini
ends of Fab region
C-termini
Fc region
CDR
complementarity determining regions
CDR in light chains and heavy chains
3 in each
Ab idiotype
defined by a unique paratope that binds to a distinct Ag epitope; paratope is the site of Ab that binds to Ag epitope
Paratope
site of Ab that binds to Ag epitope, comprised of heavy chain and light chain variable domain
Isotype
different heavy chains (constant region) comprised of 2 chains for each (eg. IgG1 IgG2a, IgM)
allotype
genetic variant that is due to mutations in C region within the same or different isotype; associated with C
IgM
primary antibody (because it is the first antibody that is released in a primary adaptive immune resposne)
IgG
most prevalent during secondary antibody responses
immunoglobulin on B cell also referred to as
B cell receptor
IgM
primary Ab secreted as a pentamere, excellent complement activator. can help with neutralizer
IgG
secondary antibody, 85% of total Ig, monomer, crosses placenta, 4 subtypes of IgG in humans (IgG1, IgG2, IgG3, IgG4)
IgG1 and IgG3
neutraliation, opsonization by phagocytosis, activating complement, Nk activation pathway, antibody dependent cellular toxicity
IgA
mucosal protectant, found in serum (monomer) mucosal IR (dimer, secretory IgA) actions include neutralization, opsonization, complement activation, Ab dependent cellular cytotoxicity (nk activity)
J chain
holds 2 ends of IgA monomer together to make dimer
IgG has what region
hinge region - flexible in binding , most prevalent in secondary immune response in both blood and lymph
Ig most prevalent in blood and lymph
IgG
Ig most prevalent in mucosa
IgA, expressed as dimer, held together by j chain
IgD
monomer, co-expresed with IgM on mature B cells, may facilitate Ag binding by naive B cells, secreted at very low levels in blood
IgE
monomer, type 1 hypersensitivity. binds to mast cells and basophils.
CD4
MCHII receptor
foreign (immunogenicity)
more foreign = more immunogenic
Size and immunogenicity
larger size (>500 kdalton) more immunogenic; more surface area / epitopes
structural diversity and immunogenicity
more diverse more likely to have a response
chemical composition and immunogenicity
proteins more immunogenic than carbohydrates. carbohydrates more immunogenic than nucleic acids. nucleic acid more immunogenic than fatty acids
neutralization
just by antibody binding to antigen, can take out toxin or pathogen and keep it from binding its receptor
istotype
A class or subclass of Ig, determed by heavy chain (specifically in the ch region)
allotype
genetic variant that is due to mutations in the Ch region within the same or different isotypes associated with Ch
the region of the antibody responsible for its biological or effector function is the
heavy chain constant region
primary reponse
first time we respond to any pathogen IgM
secondary response
IgG (in blood and lymph most prevalent) outside of mucus.
IgA - where is it secreted?
most prevalent in mucosa (muscosal protective), released by plasma cell in lamina propria - transported across enterocyte border, fastened to mucus layer in the lumen.
alpha beta TCR
less conservative in binding, more diverse.
gamma delta TCR
less variable, more conservative in antigen binding, tend to be important early in the immune response, they do seem more like innate immune cells, but are adaptive immune cells. less diverse.
MHC restriction
T cell receptors, on T cells have to bind both to peptide antigen and determinants of MHC. Even if they could recognize the peptide, but cant recognize the MHC then they aren’t selected.
CD8 T cells
MHC I presenting Ag
CD4 T Cells
MHC II presenting peptide anntigen
Expression of MHC I vs MCH II
MHC I = T cells, B cells, macrophages, dendritic cells, neutrophils compared to MCH II - B cells, dendritic cells, and thymic epithelium, some macrophage
which MHC receptor is more ubiquitously expressed
MHC I
which class MHC is expressed mainly on AFCs
class II
compare and contrast MHC I and MHC II
they have beta pleated sheets, both have alpha helices. MHC II beta chain and alpha chain = create peptide binding groove.
MHC I - designed to load ..?
loaded with cytosolic antigens (what pathogens get into cytosol?) intracellular organisms, LOADS peptides from INTRACELLULAR pathogens.
what type of t cell recognizes MHC I peptide?
CD8 T cells - when activated become cytotoxic T lymphocytes can kill those infected with intracellular pathogens!!!
CD4
- master regulator, intracellular and extracellular.
MHC II
intracellular and extracellular pathogens
Regions of MHC gene locus
chromosome 6
Class I region
encodes MHC I (alpha chain)
Class II region gene
MHC II encodes both alpha and beta chain domain
