The IPI Antibody Platform is constructed around sophisticated yeast display technology. The process hinges on a robust high-throughput strategy that involves both positive and negative selections.
Aligned with our commitment to open science, we aim to share our antibody data publicly and distribute our antibodies both commercially and through collaborations and partnerships.
To enable both biological discovery and drug development, we use human proteins as targets and select for cross-reactivity against mouse counterparts. This enables the same antibody to be used in both preclinical and clinical studies.
We use our antigens to select specific antibodies from our yeast library. Our step-by-step process eliminates candidates that cross-react with non-targets (negative selection) and enriches candidates that bind only to targets (positive selection).
Basis of Screen
Each of 15 billion yeast cells carries a different human antibody fragment (Fab) that may bind the target.
Positive Magnetic Activated Cell Sorting (MACS)
Antigen on magnetic beads binds to specific Fabs. Nonbinders are eliminated. (Repeated 2x)
Negative Magnetic Activated Cell Sorting (MACS)
Empty magnetic beads bind to nonspecific Fabs. Binders are eliminated.
Positive Fluorescence Activated Cell Sorting (FACS)
Antigen binds to specific Fabs. Fluorescent chemical detects binders. (Repeated 3x)
Strongest, specific binders remain.
To convert attractive Fabs into full length antibodies, we insert their DNA sequence into a mouse or human immunoglobulin construct and express it recombinantly using mammalian cells. We then purify the resulting antibodies and validate their specificity with various tests.
Analyze DNA sequences of best candidates and choose finalists.
Insert DNA sequences of finalist into vector.
Express recombinant antibodies from vector using mammalian cells.
Purify recombinant antibodies.
At IPI, we are continually optimizing all steps of the selection process and creating smart tools and means to predict which candidates will eventually pass our high-quality standard.
384-well plate coated with target.
Bind antibodies, added in increasing concentration.
Polyspecificity Reactivity ELISA Antibody tested against nontarget substances. Non-specific antibodies dropped from production.
Antibody introduced to sensor in BLI or SPR.
Antigen added, on rate measured. Antigen disociates, off rate measured.
Target on surface used to profile
antibody specificity and affinity.
Antibodies bind different epitopes of same antigen.
Increase in reflected light detected in SPR.
Antibodies share epitope. Second antibody displaces first. No signal change detected in SPR.
Antibody quality and quantity control
IPI has invested in the people and tools necessary to prioritize antibody quality and determine antibody yield. These measures help ensure that IPI antibodies are of verifiable quality and provide the best possible protein tools to global bioscientists.
Antibody mass-to-charge ratio measured.
Unique molecular mass calculated to confirm antibody identity.
ELISA Titer Assay Antibodies added to peptide solution. If unbound, they spin and depolarize light. If bound, they lock and polarize light. Polarization level measured to indicate yield.