antibodies/antigens Flashcards
factors influencing antigenicity
foreignness (how different are they from host proteins)
size/degradability (ability to be processed and stable in vivo)
complexity (the more antigenic sites, the more effective)
immunogen vs antigen
when an antigen bind with antibody and produces an immune response it is considered immunogen (does not always produce immune response)
Physical nature of immunogen vs antigen
immunogens typically have more antigen binding sites than antigen
antibody cross reactivity in terms of epitopes
5 classes of immunoglobulins and where found
IgG: blood
IgM: surface of B cell
IgA: secretions
IgE: mast cells, basophils
IgD: B cell receptor
IgG arrangement
4 heavy chain domains
IgE arrangement
5 heavy chain domains
IgD arrangement
4 heavy chain domains
IgM arrangement
pentameric with 5 domains and J chain
IgA arrangement
dimeric with 4 domains and J chain and Secretory component
role of Fab
where antigen binds, determines amino acid sequence (variable region)
role of constant region
determines isotype (type of antigen) and allotype
major serum antibody
IgG
complement activation
IgM (better) and IgG
primary immune response antibody
IgM
major antibody found in body fluids other than blood
IgA
antibody that crosses placenta
IgG
membrane bound to immature B cells
IgM IgD
allergy mediator
IgE
role of IgA in protecting mucus membrane
secretory component in dimeric IgA tethers it to mucus and prevents it from being degraded
function of J chain
joins monomers
function of secretory component
protects from degradation
role of hypervariable region
forms antigen binding site
different bonds
hydrogen: share hydrogen atom
electrostatic: repel/attract along center
van der waals: dipole-dipole
hydrophobic: clumping of nonpolar molecules in water
avidity
total strength of all bonds between an anitbody and antigen
affinity
strength of a single antigen-antibody interaction
specificity
different antigenic specificites have different amino acid sequences and vice versa
monoclonal antibody process
- expose B cell to antigen in mouse
- B cells with produce antibodies
- extract B cells and fuse with myeloma to form hybridoma cells
- only fused cells will be takes
- harvested and injected
why are monoclonal cells useful in diagnostic testing
highly specific and only binds to targeted cell
uses of monoclonal antibodies in healthcare
mAb theraby
