blood-brain barrier (BBB) is a unique cellular
assembly found at the interface of the blood
and the brain, composed mainly of tightly connected
endothelial cells. The BBB forming endothelial
cells are expected to have a distinct membrane
protein expression profile and there is a great
interest in finding BBB-specific membrane proteins.
In addition, antibodies against these membrane
proteins have a great potential as a means for
targeted drug delivery to the brain.
The focus of our research
is to identify BBB-targeting antibodies and
apply them in the analysis of the BBB proteome.
We are developing a method that couples the
process of antibody generation with that of
identification of the target membrane protein
antigen. This is enabled by a powerful protein
engineering platform called yeast surface display.
We have developed a way to select membrane protein-binding
antibodies, utilizing a human antibody library
expressed on yeast cell surfaces. We then exploit
a yeast immunoprecipitation (IP) method developed
to provide a highly efficient method for characterizing
membrane protein antigens. We have shown that
we can determine protein sequence identification
of the immunoprecipitated products using tandem
mass spectrometry. The library screening and
the yeast IP method are combined for highly
efficient analysis of the BBB proteome.
X. X., Cho, Y. K., Shusta,
E. V. Mining a yeast library for brain endothelial
cell-binding antibodies. Nature Methods 4, 143-5