Antibody Structure and Function Flashcards
nowmal antibody responses are
polyclonal
antibodies bind to
antigens, specifically at their corresponding epitope
multiple myeloma
- plasma cell tumor
- creates a monoclonal antibody response
- derived from a single cell
- these are all the exact same antibodies
- hone to bone marrow and dirupt hematopoiesis
- lowered WBCs with increased susceptibility to infection
- decreases RBC leading to anemia
- see a drastic increase in serum gama globulin
another word for antibody
immunoglobulin
antibody structure
- consists of a light chain and a heavy chain
- the N terminus has 2 regions with both light and heavy chains and these are the variable regions
- C term conatins only one heavy chain region and this is constant
- variable regions known as Fab (antigen binding) and constant is known as Fc (crystalizable)
- heavy chains and light chains are held together via disulfide bonds
CDR
- complimentarity determining region
- hypervariable region
- this is the regions that actually makes contact with the epitope on the antigen
classes of antibodies
- these are antibodies with different constant regions
- mu, delta, gamma, alpha, and epsilon
- within these there are subclasses
polymeric immunoglobulins
- formed by IgM and IgA
- IgM forms a pentamer, these are always made by IgM producing plasma cells
- IgA forms a dimeric antibody
- polymeric antibodies contain a J-chain protein
attachment of antibody to a B cell
- one Ig-beta and one Ig-alpha are bound to the anitbody and these are what anchors the antobody to the B cell membrane
- Igb and Iga function in delivering signals to the B cell
viral entry into cell
- virus binds to receptors on the cell surface
- receptor mediated endocytosis of the virus
- acidification of endosome triggers fusion of virus with cell and entrance of viral DNA
- Ab blocks binding to virus receptor
viral and bacterial neutralization
-Ab binds to site on capsid/bacteria which would typically facilitate entry into a host cell
opsinization via IgG and Fc-gama-R
- when immonoglobulin is bound to its target, it can be crosslinked with Fc receptors on macrophages and then endocytosed with its bound antigen
- if an immunoglobulin is not bound to its target antigen, then it can not be cross linked with Fc receptors on macrophages
- Fc-gama receptors mediate opsonization
- IgG is an important opsonin
antibody dependent cellular toxicity
- antibody binds antigens which are bound to the surface of their target cell
- antibodies are recognized by NK cells via Fc receptors
- this cross linking signals the NK cell to kill the target cell
- target cells dies via apoptosis
- NK cells express Fc-gama-R
- NK cells also induce some virus infected or tumor cells to undergo apoptosis
mast cell activation via IgE cross linking
- IgE antibodies are bound to Fc receptors on mast cells
- when these antibodies are multivalently cross linked with antigen, this causes release of granular contents
- this response function in immunity to worms
- it is also a key element in allergic reaction
what Abs do antigen specific receptor binding
all of them
neutraliation
IgA and IgG
complement activation
IgM and IgG
opsonization
IgG
ADCC
IgG
mast cel activation antibody
IgE
what processes are Fc-R dependent
opsonization
- ADCC
- mast cell activation
what antibody calss does the fetus have>
-IgG
mouth lungs, stomach, and intestine Ab
-IgA
breast milk Ab
IgA
mothers body antibodies
IgG and IgA
when the infant is born what does his immunoglobulin comp look like
- they have adult levels of IgG
- the half life is 3-4 weeks
- the infant will have protction via maternal Ab for a few months
TDAP vaccine
- tetanus, diptheria, pertussis
- recommended with each pregnancy to ensure protection for infants who are too young for vaccination but at high risk for severe illness
secretory immunoglobulin
-the predominant Ig in milk and saliva is IgA (SIgA)
secretion of IgA
- poly-Ig receptor on the basolateral surface of epithelial cells allows for receptor mediated endocytosis
- this ednosome is trancytosed
- release of IgA dimer at apical surface
common mucosal immune system
-concept that describes the fact that immune responses that occur at one mucosal site can result in IgA secreting cells migrating, via the lymphatics and blood, to distant mucosal sites
