B Cells And Antibodies Flashcards
What is on the surface of B cells that binds to antigens?
Antibodies (are all the same on the same B cell)
Antibody structure
2 heavy and 2 light chains linked by a disulfide bond
5 types of antibodies
IgG (gamma heavy chain) IgM (mu hc) IgE (epsilon hc) IgA (Alpha hc) IgD (delta hc)
2 types of light chains
Kappa and Lambda
What area of the antibody binds to antigens?
Variable region
Fragment Antigen binding
Need both the heavy and light chain to bind to the molecule
Fc Fragment of antibody
Fragment constant, binds to phagocytes, NK cells, and granulocytes with Fc Receptors
Which antibody has thee longest half life and is the major isotype in serum?
IgG
Functions of IgG
Complement activation Opsonization Antibody-dependent cellular cytotoxicity Agglutination Toxin/virus neutralization Only class the crosses the placenta Major during secondary immune response
What type of protection does IgG provide to newborn babies?
Passive protection for 5-6 months
What is the antibody produced during the initial infection?
IgM (begins to be produced around 6 months en utero)
Best agglutinator and complement activating antibody
IgM
Which antibody attacks foreign blood types?
IgM
What antibody is found in seromucous secretions?
IgA2
Secretory component
Provides protection to IgA, making 4 binding sites for anitgens
Which antibody responds to worms and is prominent in allergenic reactions?
IgE
What types of cells does IgE bind to?
Fc(episilon)R on basophils, mast cells, and eosinophils
What antibody triggers B cell differentiation?
IgD
What is the largest antibody wand where is it usually found?
IgM and intravascular
Which antibodies have a joining region?
IgA and IgM
RAG genes code for what?
Kappa light chain
Deficiency in functional RAG genes causes what disease?
SCID
Junctional diversity
Imprecision in joining of VDJ gene segments leads to nucleotide additions/deletions, resulting in amino acid changes
N-region diversity
terminal deoxynucleotidyl transferase adds nucleotides not encoded in the DNA template
What are the 2 fates of completed antibodies?
Cytoplasmic tail attachment to the B cell OR secreted
Class switch
Areas where DNA can over loop on itself to switch which antibody is produced
What enzyme is required for class switching?
AID enzyme. Activated when B cell receives T cell help
Hyper-IgM syndrome
Deficient in CD40, CD40L or AID, so are stuck making IgM. Highly susceptible to cancers
What mediates n-region diversity?
TdT
Which antibody responds to worms and is prominent in allergenic reactions?
IgE
What types of cells does IgE bind to?
Fc(episilon)R on basophils, mast cells, and eosinophils
What antibody triggers B cell differentiation?
IgD
What is the largest antibody wand where is it usually found?
IgM and intravascular
Which antibodies have a joining region?
IgA and IgM
RAG genes code for what?
Kappa light chain
Deficiency in functional RAG genes causes what disease?
SCID
Junctional diversity
Imprecision in joining of VDJ gene segments leads to nucleotide additions/deletions, resulting in amino acid changes
N-region diversity
terminal deoxynucleotidyl transferase adds nucleotides not encoded in the DNA template
What are the 2 fates of completed antibodies?
Cytoplasmic tail attachment to the B cell OR secreted
Class switch
Areas where DNA can over loop on itself to switch which antibody is produced
What enzyme is required for class switching?
AID enzyme. Activated when B cell receives T cell help
Hyper-IgM syndrome
Deficient in CD40, CD40L or AID, so are stuck making IgM. Highly susceptible to cancers
What mediates n-region diversity?
TdT
