Antibodies-antibody Classes, And Immunity Flashcards
T-helper subsets
TH0 (undetermined T-helper)
- TH1
- TH2
Which T helper cell regulates cellular immunity?
TH1
-delayed type hypersensitivity
Macrophages invasion
What type of T helper cell regulates humoral immunity
TH2
- antibodies
- allergic responses
Antibody shape
Large Y shaped glycoprotein (lots of AA)
What are antibodies produced by
B cells
What ar the components of antibodies
Two heavy chains
Two light chains
Two cleavable fragments
What are the two heavy chains on antibodies
- AA sequence determines isotype (IgG…etc)
- unique to each class
What determines the iostype of an antibody (IgG, IgM..etc)
AA sequence on heavy chains
What are the two light chains in antibodies
- either kappa or lambda
- shared by all classes
Two cleavable fragments on antibodies
- Fab-antigen binding
- Fc-tail that cells go after
Where do macrophages attach to antibodies?
Fc-site
What holds the heavy chains together?
Disulfide
What kind of immune response is IgG?
Secondary
Structure of IgG
Monomers
-subclasses differ in # of disulfide bonds and hinge length
What is the major Ig in plasma?
IgG
What is the only Ig class to cross placenta via Fcy receptors
IgG
What do IgG bind to
APCs and PMNs via Fcy receptors
What two antibodies fix complement
IgG and IgM
Structure of IgM
Pentamer
-J chain connected 5 identical u monomers
What is the third most common Ig in plasma
IgM
Firs Ig to be made in fetus, and first to be made by virgin Ag-stimulated B-cells
IgM
Primary immune response
Structure of IgA
Monomers and dimers
Where is the monomer form of IgA found
Plasma
Where is the dimmer form of IgA founds
Secretions
What connects the IgA monomers
J chain
Secretory piece in IgA
- made in epithelial cells
- aids in transport and protects from degradation
- help it secrete in tears, saliva, etc
What is the second most common Ig in plasma
IgA
Major class of Ig in secretions, important in mucosal immunity
IgA
Does IgA fix complement
No
Found in places you don’t want inflammation! GI
Where is IgD primarily found
On B cell surfaces
-receptor for antigen
What happens if an antigen binds IgD?
It’ll pull it inside the B cell
Can ingest and present
Structure of IgE
Monomer
Least common Ig in plasma
IgE
Binds tightly to Fce receptors on basophils and mast cells
IgE
Where are mast cells always located
Tissues
What happens to blood pressure in allergic reaction
IgE binds to allergen, causes mast cell to produce histamine
-drops BP DRASTICALLY
Involved in allergic reactions
IgE
Involved in parasitic infections
IgE
-binding of eosinophils to IgE-coated parasites results in killing of the parasites
What releases histamine
Mast cells
What arms the mast cells, waiting to bind to allergens
IgE
IgE is docked on
Mast cells
- allergen crosslinks IgE
- inflammatory mediators are released
What do all antibodies do
Neutralize and agglutinate
Why does primary response take a long time
- producing own antibodies
- IgM to IgG switch takes some time
What causes the IgM/IgG switch
Controlled by interleukins and co stimulators signals from TH2 cells
What predominates in mucosal immunity
IgA
Viral window in HIV
Long viral window, wont produce antibody for up to 6 months
What is viral window
Infected, but hasn’t made any antibodies yet
What’s the difference between active and passive immunization
Artificial is with altered agent or its antigens
Passive is with antibodies
Active immunity
Making own antibodies
Passive immunity
Receiving other antibodies
Immediate but short lived
Passive immunity
Artificial passive vaccines
- immunoglobins
- antivenom/antitoxin
Artificial active vaccines
- live
- killed/fixed
- toxoid
- subunit
- DNA
Natural active
Natural infection
Post rabies prophylaxis
- RIG + antigen
- helps make one antibodies
- RIG: if already had exposure
