Antibodies Flashcards
What protein fold family do antibodies belong to?
Immunoglobulin
Where are antibodies produced?
B-lymphocytes
What type of immunity do antibodies mediate?
Humoral/adaptive
What is another name for antigen?
epitope
Where is variable region diversity found?
In hypervariable loops to bind antigen
What processes contribute to variation?
V(D)J recombination
Combinatorial diversity
Junctional diversity
Somatic hypermutation of mature B cells
How many antibodies can V(D)J produce?
6000
What affinity do antibodies have for antigen?
High: Kd 10^-10M
What is another name for hypervariable region?
Complementarity determining region
What type of interactions do antibodies use to bind antigen?
Non-covalent (reversible)
What are the 3 responses caused by antibody-antigen binding?
Osponisation to neutralise, for phagocytosis or active complement cascade
What does ADCC/cell mediated cytotoxicity target?
Cells expressing antigens on surface
Which Ig is first to be secreted?
IgM or IgD
What is the structure of IgM?
4 heavy domains
pentameric
Where is IgM found?
In blood as too large to leave
What responses does IgM mediate?
Agglutination to neutralise
complement cascade
Which is the most common antibody?
IgG
What is the structure of IgG?
4 isotopes
3 heavy chains
Where is IgG produced?
In lymph nodes and spleen following infection, causing class switch recombination
What function does IgG have?
Neutralisation, phagocytosis and activates complement cascade
Where is IgG found?
In blood, tissues and can cross placenta
What is the structure of IgA?
Monomeric or dimeric
3 heavy chains
What function does IgA have?
Found in mucus to neutralise antigens proir to infection
What is the structure of IgE?
4 heavy chains
Bound to Fc receptors on basophils, mast cells and eosinophils
