Antibodies part 1 Flashcards
What does electrophoresis separate serum proteins into?
Albumin
Alpha
Beta
Gamma
What are some other names for antibodies?
Gamma globulin
Immune globulin
Immunoglobulin
- infact antibody is specific to a toxin and thus immunoglobulins are the big 5
IF you were to have a huge spike in Gamma on an electrophoresis what should you suspect?
Lymphoma
- massive clonal expansion because you have a ton of antibodies produced
What are some adapter molecules for antibodies?
Immune complex
Immune complex/pathogen
Target Cell/pathogen
Antigen
How many variable and constant regions are found on the heavy chain?
1 variable
3-4 constant
How many variable and constant regions are found on the light chain?
1 variable
1 constant
- the C domains are structurally similar throughout
what type of bond holds regions of the antibody together?
Disulfide bonds
What region of the heavy chain interacts with complement and how does it do this?
CH2
- done because patches of carbohydrates push this region out
- this is how antibodies initiate inflammation
What causes isotype switching and where?
Cytokines and CD40L
- germinal centers of LN
What doe naive B cells express in terms of immunoglobulin on their surfaces?
IgM
IgD
What is the most abundant antibody in the body?
IgG
- 4 subtypes
- crosses placenta (passive infant immunity)
- Opsonized bacteria
- neutralizes Bacterial toxins and viruses
- fixes complement
- monomer
- delayed response
What antibody is secreted as a dimer and what connects this dimer?
IgA
- J chain
- monomer in circulation though
- 2 subunits
What is the purpose of IgA and where is it produced?
Prevents bacterial and viral attachement to mucous membranes
- produced in GI tract (ex. Payers patches)
- Protects gut infections like Gardia
- most abundant Antibody but not in serum concentrations
Where is IgA released from?
Tears, saliva, mucus, breast milk
- picks up 2’ component from epithelial cells
What antibody is a pentamer when secreted? What binds the units of it?
IgM
- J Chain
- Part of immediate response to antigen
- Fixes complement and doesnt cross placenta
- Monomer on B-cell
- pentamer allows for most efficient binding of complement while humoral response evolves
- 2 subunits
Where is IgD primary found?
B Cell and tract in serum
- unknown function
What is IgE secreted as?
monomer
- Binds mast cells and basophils
- Cross link when exposed to antigen cause huge release of inflammatory mediates like histamine (TYPE I hypersensitivity)
- lowest conc. in serum
- mediates immunity against worms
What is the basic structure of an antibody?
2 heavy
2 light chains
FC
FAB
How many kinds of heavy chains are there?
5 Gamma Alpha Mu Epsilon Delta
How many light chain varieties are there?
2
Kappa and Lambda
- each immunoglobulin will either be kappa or lambda like no mix and match
What happens to the heavy and light chain varieties during a isotype switch, say IgM to IgA?
Switch heavy chain from Mu to Alpha
- light stays the same
What is the complementarity determining regions?
3 ares along the variable chain that contains different amino acid sequences
What is valence and what does it mean?
Number of antigenic determinants (epitopes) that can bind any antibody molecule
- thus 10 for secreted Igm
- 4 for IgA
- 2 for monomers
Can isolated Vl and VH bind?
no
What are allotypes?
minor allelic differences in sequence of immunoglobulins between individuals
- thus everyone produces original and and individualized antibody to the same antigen
What are idiotypes?
unique variable regions that bind specific antigens
What is the most efficient form of IgG in which to be activated by complement?
hexamer
- need 2 to get complement binding but 6 is most efficient
