Antibodies and Antigens Flashcards
What are the effector properties of Ab’s?
Toxin neutralization
Activation of complement
Opsonization
Direct antibacterial activity
Structure of Ab?
Four polypeptide chains, two light and two heavy bound by covalent disulfide bridges.
Describe th eheavy and light domains?
H and L divided into variable and constant regions. The variable regions contains the Ag binding site and the C regions determines the biological properties of Abs.
What does Papain do?
they cleave Ab into two Fab fragments and an Fc fragment.
Allows separation of two monovalent fab fragments.
What does pepsin do?
Generates single bivalent antigen fragment F(ab’)2
What are the two types of L chains?
Kappa and lambda
What determines the class of antibody?
The five different types of H chains
A,G,M,D,E
Membrane IgM
Long tail into the plasma membrane to transmit signal to inside the cell. IgM is on the cell membrane
Hinge?
Allows the distance between angiten binding sites to be moved closer or further apart
What Ag’s are recognized by Ab’s?
Everything!
Conformational Determinant- important for toxin neutralization
Linear determinant– can recognize denatured or not denatured
Neoantigenic determinant created by proteolysis.
Also recognizes nucleic acids and polysaccharides
What Ig has the highest affinity
IgG
Ab’s formed in primary response have higher or lower affinity than memory response?
Lower affinitiy
Avidity?
Ability of an Ag to bind to Ab based on affinity and valence
Valence?
Number of Ab binding sites
2 for IgG, IgD, IgE and Serum IgA, and Membrane IgM
4 for secreted IgA
10 for serum IgM
What kind of Ag recognized by T cell Receptors?
Peptide MHC complexes
What kind of Ag can be recognized by immunoglobins?
Proteins, lipids, polysaccharides, small chemicals
Who has higher affinity Antibody or T cell receptor?
Antibody
Who has higher affinity Antibody or T cell receptor?
Antibody
B cell receptor generation?
Bone marrow: lymphocyte precursor cells to pre b cell. Pre B cell synthesizes its pre-B cell receptor (receptors made one at a time-surrogate light chain). Pre B cell receptor tested to make sure signals are received correct, incorrect ones degraded.
B cell where is it immature and mature?
B cell is immature after leaving bone marrow, but completely differentiated. It goes through circulation and is activated (mature) in the spleen.
secretable form of immunoglobins?
Dont contain the transmembrane receptor
Where is IgA found?
GI tract lumen. It is a dimer with a secretory domain. Secreted by plasma cells below epithelium. The secretion protects IgA from degradation by proteases.
Monomer in the blood
What does a proliferating B cell differentiate into if exposed to IFN-y?
IgG3 for phagocytosis
What does proliferating B cell differentiate into if exposed to TGF-B?
Mucosal defenses IgA
