Flashcards in Cell mediated and humoral immunity (10) Deck (49):
What cells can entire the secondary lymphoid tissue and possibly acquire membrane IgD?
Nieve B cells expressing membrane IgM.
Where do activate B lymphocytes divide and differentiate?
2ndry lymphoid tissue.
What mediates the humoral immune response?
Soluble antibody proteins.
What is an example of secondary lymphoid tissue other than the lymph nodes?
What Ig class is commonly found in dimers?
What Ig class is commonly found as pentamers?
What is the main antibody in tissues?
What do the IgG subclasses mainly differ in?
Length and number of disulphides in hinge region.
What can IgG activate?
What FC receptors does IgG bind to?
Phagocytes and NK Cells.
What can IgG do that other immunoglobin classes can not?
Cross the placenta.
What receptor can IgG bind to on the trophoblast?
What property of IgG means it can bind to FcRN on the trophoblast?
Long serum half life.
What sort of response is IgG important in?
Secondary or memory responses.
Why is IgM usually serum restricted?
It has a mw of 970,000 daltons
What does IgM not have?
A defined hinge region Instead it has a 'functional hinge'.
IgM has 5 subunits. What else is associated with its structure?
What response is IgM important in?
What is IgM good at (2 things)?
1. Being a agglutinator to a particular antigen
2. Activating complement
Isotype switching occurs on which Ig class to produce what other Ig classes.
Occurs on M to produce G, A or E.
What is usually required to allow for isotype switching?
T cell help via cytokines.
The level of IgM is higher in the primary response compared to the secondary response. True or false?
False. It is the same level in both responses.
IgA is either monomeric or dimeric. True or false?
False, it can also be polymeric.
What subclass of IgA is found in primates?
What contains IgA?
What Fc receptors does IgA bind?
Why was IgA thought to originally have little importance?
Where in the body is IgA present?
Secretions and mucosal surfaces.
What Ig classes contain the J chain?
M and A.
Where would you find IgA that contains the J chain?
What is found with secretory IgA?
IgA dimer, J chain, secretory component.
Polymeric Ig molecules (M and A) can undergo specilised transport via what receptor?
How much IgA does mucosal lymphoid tissues produce each day?
Where does the Poly-Ig receptor transport IgA/M too/ from?
From the submucosa via epithelial cells into the lumen.
What is it thought IgA could have a role in?
Fighting infection passively.
What percentage of serum Ig is IgD?
Where is IgD found?
As an antigen receptor on many B lymphocytes, often with IgM.
Where in the body do plasma cells/ B cells produce IgD? What does IgD do here?
Upper respiratory tract. Here it can interact with receptors on basophils inducing antimicrobial, inflammatory and B cell stimulatory factors.
Monomeric IgM contains a functional hinge. What other Ig class also contains this?
What Ig class is found in the smallest amount in serum and what percent is it found at?
E. Only 0.0003% of serum is this class. This is a 'trace' level.
What can IgE bind to?
High affinity FcR receptors on mast cells and basophils.
What is released during mast cell degranulation?
Histamine and other inflammatory mediators.
What is the main biological role for immunogloblins?
Label pathogens for elimation and destruction.
All antibodies are at least what?
What antibodies neutralize toxins?
G and A.
What antibodies immobilise pathogens?
What antibodies prevent the pathogens binding to host?
G and A
What antibodies agglutinate particles such as bacteria?
M and A.