Antibody Screening Solutions Made Easy - 33

Antibody Screening Solutions Made Easy * Antibody Factory in a Dish

cocktails. Laboratory methods for isolating
antibodies, including phage display, EBV immortalization, yeast display, and humanized
animal models, all depend on large-scale screening to identify specific antibodies. Techniques
like antigen-specific B cell sorting and single
cell cloning have improved antibody identification, but only work on high-affinity antibodies.
Batista's team exposed B cells derived from
healthy patient blood to "a cocktail of nanoparticles" attached to an antigen and CpG oligodeoxynucleotides (CpG), which are DNA
fragments that can activate the TLR9 signaling
protein when integrated into a cell.
"There is only one trick there," says Batista.
Introducing CpG alone in solution will activate
the B cells indiscriminately. "But the cells you
are interested in, they are one in 10,000, one
in 100,000; how do you identify them?" asked
Batista. "If you attach the ligand together with
a protein to a nanoparticle, the TLR ligand becomes refractory to the cell, unless you internalize
it through the B cell receptor. And the only cells
that do that are the cells that are able to bind
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the protein on the nanoparticle. I am exploiting
the capacity of the B cell receptor to capture
what is outside the cell and bring it in. Because
the TLR receptors are inside the cell, they only
get exposed to the ligand when the
B cell brings it to them."
The Batista team was able to produce a large
panel of high affinity human mAbs within a few
days. Then, taking memory B cells derived from
healthy donors that had not been previously
exposed to that particular antigen, they validated their results in successive experiments
using a gp120 protein on the surface of the HIV
envelope, multiple strains of the H1N1 Influenza
A virus, as well as antigens of tetanus.
According to Batista, a limitation of the study
was that it did not produce a complete immune
response in culture. A next step is to enable
affinity maturation in vitro. Batista's personal
mission is to develop an HIV treatment-but
in the meantime, this technique could provide
quicker immunity testing as well as generate
mAbs in vitro without needing human clinical
trials. n

Rapidly creating large amounts of monoclonal
antibodies in vitro could hold the key to
developing treatments for diseases like
cancer or HIV infection. NIH

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Antibody Screening Solutions Made Easy

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