Antibody Overview | Phage Display Overview | Utility of Selected Antibodies | Glossary
Based on their unique properties, antibodies have been widely
used as powerful tools in diagnostic and therapeutic applications as well as
in basic biomedical research. The availability of sFv antibody phage
display libraries has greatly expanded our ability to isolate antibodies
against unlimited targets. As the size and genetic complexity of human sFv phage
display libraries have increased in size, a greater number of high affinity
antibodies that are directed against more epitopes on the target protein have
been isolated. Libraries of the sizes that we have developed (12 and 15 billion
members) have provided high affinity human sFvs against all targets that we
have examined to date.
The whole phage display screening/selection process takes about
three to four weeks to complete, with the initial identification and isolation
of antibodies usually within 10-14 days and the genetic characterization of
the antibodies within 1-2 additional weeks. The selected antibodies are fully
human in nature, which reduces the likelihood of adverse immunological
responses when used in human. As the phage
antibody contains the genes that code for the antibody proteins, these genes
can be recovered and are available for use in different bacterial, eukaryotic
and mammalian expression systems to produce human monoclonal antibody fragments,
sFv-IgG1 fusion proteins, or whole human monoclonal antibodies.
One can easily imagine use of the selected antibodies in imaging and immunotherapy.
The selected antibodies can also be used as intrabodies.
By definition, intrabodies are antibodies that are directed against target molecules
that are inside a cell and expressed within a particular cellular compartment
as directed by the intracellular localization signals genetically fused to N-
or C-terminus of the antibody. Intrabodies have wide applications in dissecting
target protein function, in target validation and functional genomics, as well
as acting as potential therapeutic reagents. For a recent comprehensive review
on intrabody technology, please
see the reference by Zhu and Marasco, 2003. Dr. Marasco’s laboratory
at DFCI has created a set of intrabody expression vectors over the years that
can accept the sFv antibodies from phage display selection with easy Sfi I/
Not I compatible restriction sites. It is the Center’s hope that in the
near future the Center will be able to help the NFCR investigators in building
intrabodies for gene "knock-out" and gene therapy experiments.
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