BSI - Products and service

PlasmScan™ and QuantiPlasma™ Antibody libraries

While gene expression profiling is a widely used and highly proven technology for the dissection of disease and the unraveling of underlying pathological processes, proteome profiling is, in contrast, still in its infancy*.

BSI’s monoclonal antibody proteomics tools are specifically designed to fill the gap!

BSI’s goal is to provide the research community with comprehensive mAB libraries generated against the epitome** of the human plasma proteome. At BSI we use our robust technology to produce increasingly large sets of mAB libraries that will cover the entire human plasma epitome.

Our mAB libraries provide the tools that enable the research community to discover new disease specific biomarkers via robust antibody micro-array profiling of human plasma samples (see our poster on the use of BSI mAbs to discover biomarkers for lung cancer).

The mAB libraries are ready for profiling your samples via micro-array technology provided by our partners.

General features of BSI’s mAB libraries:

Suitable for biomarker discovery by human plasma profiling (see our poster describing BSI mAb libraries and antibody microarrays).

Contain non-redundant antibodies against the native plasma protein epitome

Antibodies recognize native protein structures and post-translational modifications (Wang, D., et. al. Antigen Identification and Characterization of Lung Cancer Specific Monoclonal Antibodies Produced by mAb Proteomics. J. Prot. Res., accepted for publication)

Antibodies selected solely based on technical criteria in a hypothesis-free manner: no theoretical bias or preconceived notions

Antibodies and cognate antigens are being characterized in parallel with the enrichment of the libraries.

PlasmaScan™:

PlasmaScan 80 / PlasmaScan380 antibody arrays contain 80 and 380 (respectively) different mABs each reacting with different epitopes of the human plasma proteome. Monoclonal antibody microarrays printed in single or multiple copies on planar slides are offered by ArrayIt Corporation and MicroBioChips SAS. Processing of the slides is also available (please inquire).

How to use the PlasmaScan antibody arrays

Step 1. Sample preparation and proteome profiling.
Plasma samples from clinical cohorts require sample preparation. During the sample preparation process plasma proteins are labeled and the labeled samples are incubated with the microarray slides under controlled conditions. For optimal signals the plasma proteome may be subjected to depletion to remove abundant proteins (see our sample preparation services)

Step 2. Characterization of cognate targets of individual mABs.
Comparison of plasma proteome profiles will result in the identification of mABs that detect quantifiable differences between clinically and/or biologically different sample sets. As needed, BSI and our partners will provide the user with available data on each mAB (e.g., protein ID, epitope/mimitope, V region sequence of light and heavy chains) and a sufficient quantity of purified mABs to further characterize the cognate antigen recognized by the mABs by the user (see our mAB production and characterization services).

QuantiPlasma™ - Global Protein Profiling System

The Global Profiling System antibody arrays, developed using antibodies from BSI’s QuantiPlasma™ antibody library, allow precise proteome profiling without sample labeling. The first product contains 69 mABs each reacting with a different epitope of the human plasma proteome. A version with 250 mABs is under development. The antibodies work in “tracer inhibition assays” utilizing stabile labeled tracers for the profiling experiments, which are included in the kits. In the assay, your sample, e.g. plasma samples dilutions from patients will compete with the labeled tracer.
This turnkey microarray-based plasma profiling system is a solution developed with our partner Randox Laboratories Ltd. for precise protein profiling of human plasma on their Evidence Investigator platform.

Step 1. Profiling
Plasma samples from clinical cohorts are ready for profiling with the Global Protein Profiling System. Different dilutions of the clinical samples are incubated with the microarray slides under controlled conditions in the presence of labeled tracers from the kit.

Step 2. Characterization of cognate targets of individual mABs
Comparison of plasma proteome profiles will result in the identification of mABs that detect quantifiable differences between biologically different sample sets. As needed, BSI and our partners will provide the user with available data on each mAB (e.g., protein ID, epitope/mimitope, V region sequence of light and heavy chains) and a sufficient quantity of purified mABs to further characterize the cognate antigen recognized by the mABs by the user (see mAB production and characterization services).

*Proteomic profiling of human plasma by shotgun mass spectrometry is a popular approach for the discovery of novel biomarkers. This approach suffers, however, from limitations in reproducibility and sensitivity due to the wide dynamic range of protein concentration in plasma often necessitating extensive upfront processing to remove abundant proteins. Furthermore, mass spectrometry based approaches require a costly and extensive infrastructure. Finally, validation of results are often further hampered by the lack of available immuno-affinity reagents. A viable and economical alternative is the use of monoclonal antibody microarrays directed against natural human plasma proteins (see our publications and posters for more information)

**Monoclonal antibodies are essential components of protein detection systems, and today represent the most specific and sensitive tools for qualitative and quantitative detection of proteins in complex analytes such as human plasma.. Multiplex protein detection is feasible via antibody microarrays (reference) . Antibodies recognize short specific three dimensional peptide structures (often not linear sequences) on the surface of proteins. These uniques structures are called epitopes. The sum of all the epitopes of the human plasma proteome is the epitome. Individual protein species often have multiple epitopes.

Services:

Sample preparation

Abundant proteins are depleted from the samples using different affinity (mainly immuno-affinity) chromatography procedures and the depleted samples are labeled for recognition. The type of depletion depends on the end-user’s preference. Sample preparation is followed using strict quality control procedures. Protocols are provided upon request.

mAB production and characterization

Mouse monoclonal antibodies are produced either in mice or in disposable bioreactors. Immunoglobulins are purified from ascites fluid or bioreactor culture medium using chromatography procedures. Antibody purity is confirmed by capillary gel electrophoresis. 50 or 100 g aliquots are available, production of new batches requires 6-8 weeks. Characterization of mABs and antigens may be available upon request.

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