Antibodies Flashcards
What is Fc and what is Fab?
Fc= Contant region –> interacts with cells via specific Fc Recetors. Determines effector function
Fab= variable region for specificity- binds antigen
Describe location of IgA
In serum as a monomer (2H/2L- 2 antigen binding sites).
Major Ig present in external secretions (colostrum, milk, saliva) as a dimer (4 antigen binding sites)
Which Ig has a secretory component?
IgA! Has SC and J chain.
SC will aid in transepithelial transport of IgA and stabilizes IgA again degradation
Which Ig is first line of defense against microbes on mucosal surfaces?
IgA!
Describe location and function of IgD
Present in low quantities in circulations. Function is antigen receptor on B CELLS.
Which Ig plays a significant role in enhancing acute inflammation and provides protection from worms and allergies?
IgE!
Binds FceR1 on MAST CELLS
Where is IgG most abundant? Describe function
Most abundant in blood as a dimer.
Provides bulk of immunity to most blood-borne microbes
Function:
Can cross placenta and provide passive immunity!
-Opsonizes
Which Ig provides passive humoral immunity to the developing fetus?
IgG
Which Ig acts as B cell receptor?
IgM
What Ig is the first antibody (along withIgD) to be expressed on a naive B cell?
IgM!!
Where is IgM present? Describe function
PRIMARY RESPONSE with IgD
In blood and sometimes tissues.
In blood it is a pentamer with a J chain
Function: Acts as a BCR
Has a high avidity
What is Allelic exclusion?
When you have one specificity of L and one specificity of H chain for one individual B cell
What do the V families that encode part of the H chain contain?
CDR1 and CDR2.
The VDJ rearrangement specifies CRD3
