Antibodies Flashcards
3 process that antigen antibody complex can stimulate
Complement activation
Opsonisation
Cell activation by change in shape of Fc receptor when antigen binds
What are the Fab and Fc parts of an antibody
Fab = part that binds to antigen Fc = part that is constant
What other disulphide bonds are found in immunoglobulin?
Internal intrachain disulphide bonds
Within chains
What are the three hypervariable regions called?
Complementary determining regions
CDR amino acids part of antibody that binds to antigen
Constant region = beta pleated sheets
CDR = end of V domains
What forces are involved in antibody antigen interactions?
Everything but COVALENT
Affinity vs avidity
Affinity = strength of interactions between ONE antigen binding site and ONE epitope
Avidity = strength of all interactions between antibody with MANY binding sites and antigen with MANY epitopes
What is cross reactivity?
Antibody for one antigen can bind to another that is similar e.g cow pox and small pox
IgG
Gamma heavy chain 4 types Most abundant Move across placenta Activate complement by classical pathway Sub groups vary in hinge region
IgA
Second most abundant 2 sub groups Alpha heavy chain Protects mucosal surfaces Secretory molecules attached to it by J chain
How does dimeric IgA get across epithelial to lumen?
IgA produced by plasma cell
IgA binds to poly Ig receptor on basolateral membrane
Endocytosis into epithelial
Poly Ig receptor cleaved
Secretory component attached to IgA and secreted into lumen
IgM
Mew heavy chain
Pentameric
Joined by J chain
Agglutination
IgD
Delta heavy chain
Low conc in serum
Involved in B cell development
IgE
Epsilon heavy chain
Produced when allergic disease or parasitic infection
Bind to Fc receptor of mast cell and basophils
