Antigens and Antibodies Flashcards
What are alloantigens? Give an example.
Tissue specific antigens, which is present in one individual species but not in others.
Example: Blood type
What is the difference between the ligands for T-dependent antigens and T-independent antigens?
T-dependent antigens are proteins. T-independent antigens are polysaccharides and proteins.
What kind of epitopes are recognized by α/β T cells?
Linear proteins. NOT free peptides.
How do γ/δ T cells differ from α/β T cells?
The recognize lipid antigens, can recognize DAMPs, and are not MHC/HLA restricted.
What are haptens?
Small molecules that cannot induce an immune response alone. Will induce a response when coupled with a carrier protein. Clinically important in drug allergies and vaccine design.
What are superanitgens?
Antigens that invoke a strong immune response by binding “around” the TCR and MHC. Can lead to shock syndrome.
How are the Fab and Fc regions of antibodies isolated?
Through papain digestion
How is the two separate Fab regions isolated and the Fc region degraded?
Through pepsin digestion
What is the difference between the Allotype and Idiotype of an antibody?
Allotype: Allelic differences on the H chain
Idiotype: Differences in the variable regions
What are the main functions and properties of IgM?
First antibody produced by fetus. Antibody produced in primary response. It is a pentamer, with 10 antigen binding sites in total (5 x 2). Also found on B cells as a monomer.
What are the main functions and properties of IgG?
Most abundant antibody class in serum. Predominant Ab of secondary immune response. It is also the only antibody that can cross the placenta.
What are the main functions and properties of IgA?
Part of the secondary immune response. Predominantly found in mucosa: colostrum, saliva, tears, mucus. Secreted as a dimer.
What are the main functions and properties of IgE?
Part of the secondary immune response. Normal function is against Helminth, but also plays a role in asthma and allergies.
What are the main functions and properties of IgD?
Membrane bound on B cells in addition to IgM. Full function is not well understood.
What FcR is only found on IgG and what is its function?
FcRn, signals the cell to release the IgG back to the extracellular environment.
