Thrush -Immunoglobulins Flashcards
The Ag specificity of a B lymphocyte is due to the membrane bound _____. A single Ab can only bind one epitope. Once a B cell is activated, it can develop into a __ cell secreting soluble Abs. A given B cell produces Abs with ___ antigenic specificity. ___selection and ___ allows for the expansion of B cells speficic for one antigen.
antibody; plasma; ONE; Clonal; proliferation
Isolation of monoclonal Abs from myleoma patients and those producing ____ ____ proteins allowed for characterization of Ig structure. They produced in urine of patients with overproduction of light chains.
Bence- Jones
An Ab has 2 identical heavy chains and light chains. Heavy chains joined together by ____bonds in the hinge region. Light chains joined to heavy chains by ___bonds in the CL region. There are ____ classes of heavy chains. There are ___ types of light chains (kappa or lambda). Both heavy and light chains have ___ disulfide bonds. Ab binds Ag at the ____terminal end (VH and VL). ___ binds antigen. ____ has biologic activity
disulfide disulfide 5 2 intrachain N Fab Fc
Where is variability concentrated
Complementarity determining regions: CDR1, CDR2, and CDR3 aka hypervariable regions; framework regions are areas that are less variable
Fab actually binds to ____. Fc has an effector function and has constant domains of heavy chain only which is det by which type of isotype produced. IgG and IgA have ___ due to minor aa differences in C region
epitopes; subclasses
Plasma cells dont have ___ on their surface, they only secrete it. IgM in the secreted form is a _____held together by J chain and is the ____ of the antibodies. IgG, D and E are ____ in the membrane bound form and secreted form. ___ is a dimer in the secreted form.
antibodies; pentamer; largest; monomers; IgA
____is the Ab in the highest concentration in serum. ____ is in lowest concentration. 2 classes of Ab that can activate complement are ___ and ___.
On surface of mature, resting B cell there is ____ and ____. ___ is involved in mucosal transport. ___ induces mast cell degranulation
IgG; IgE IgG and IgM IgD and IgM IgA IgE
what are properties of IgM
- pentameric when secreted from plasma cell. ; highest avidity; joined by j chain
- Monomer on surface of B cell
- appears first during the primary immune response.
- best at Cā activation
- best agglutinating Ab
what are properties of IgG
- always a monomer
- 2 Ag binding sites
- 4 subclasses
- Predominant Ig in blood and lymph (longest half life)
- appears in late primary and early secondary immune response.
- can activate Cā
- some subclasses cross placenta
- opsonin and mediates ADCC
what is opsonin
agent that stimulates phagocytosis
what are characteristics of IgA
- secretory Ig; monomer on surface, dimer when secreted; held together by j chains
- muchophilic; attaches to epithelium and traps Ags in mucous where lysozyme can help degrade.
- 2 subclasses
- major Ig in the body; highest concentration! (IgG is highest in serum and lymph)
what are characteristics of IgD
- monomer
- second receptor on B cell (after IgM); coexpressed on surface of B cell.
- unknown function; maybe plays a role in initial activation of B cell.
what are characteristics of IgE
- Binds to basophils and mast cells.
- lowest concentration in serum.
- when binds Ag, causes degranulation of mast cell = allergic reaction
- protection against parasitic worms; causes acute inflammatory reacion.
what are isotypes
classes of antibodies; determined by C- regions of the heavy chain; some describe light chain isotypes as well.
what are allotypes
allelic forms of the same protein that can vary within a species.
