Therapeutics Flashcards
For what type of diseases is immunogenicity a problem?
Mainly for chronic conditions where repeat administration is needed.
What does protein turbidity measure?
Protein aggregates scatter light in the visible wavelength region when formed in aqueous solution. So solution turbidity = a convenient method for monitoring protein aggregation in biochemical assays.
Can amino acid changes affect Tm?
Real data - single AA change led to 5C change in thermal stability.
Found at interface between Vh and Vc domains.
Mus ensure introduce into buried residues to prevent immunogenicity.
(a few = 10 - same as stability of protein folding!!)
What is ABDEG?
An example of increasing half-life.
engineered IgG to bind FcRn with higher affinity (reduced dependence on pH) –> inhibition of interaction of ENDOGENOUS IgG with FcRn.
Potential use for reducing IgG []s in patients with Ab-mediated diseases.
Why are almost all marketed Abs in the IgG format?
And what is the broad architecture of antibodies?
IgM has limited therapeutic potential as ~ 1 MDa so complex and difficult to manufacture / can’t reach targets beyond vasculature.
Modular domain.
Give an example of the issue of immunogenicity in patients.
They can react with endogenous proteins. E.g. People with naturally low levels of EPO, antibodies to this neutralise endogenous EPO leading to pure red cell aplasia.
What is the difference between chimeric and humanised antibodies?
Chimeric = fusion protein of region of genes from 2 different species (mainly mouse variable and human constant).
Humanised = From non-humans but sequences modified. (needs CDR grafting onto human acceptor framework.)
Imab vs Umab.
Why are results from CDR grafting often poor?
Some framework residues are;
Directly involved in AN binding (surface exposed / adjacent to CDRs)
Responsible for holding CDRs in correct conformation (buried and form Ig core / buried and form contacts with CDRs)
