Antibody Screening

Antibody Screening

Antibody Screening

Antibody Screening

Antibody Screening

Working principle

VERAXA efficiently finds functional monoclonal antibodies (mAbs) – out of entire immune repertoires with several million B cells – in less than 48 hours.

Current strategies for the discovery of functional antibodies typically include two separate and consecutive steps. In the first screening step, a biased sub-pool of strongly binding antibodies is sorted out. In the second step, only this sub-pool is analyzed for function. As the desired antibody function is not directly correlating with binding strength, many of the rare functional and therapeutically precious antibodies are lost in the first screening step and are hence not available for future developments. Moreover, the serial processing of the two steps reduces diversity,increase the probability for errors, is time consuming and often results in false positives hits, not suitable for further use.

VERAXA has cut this Gordian Knot by replacing the common two-step approach with a single functional screening step, sorting out functional antibodies directly. We deliver with enormous speed and highest reliability all of the precious hits that do not only bind but exert the desired modulatory function on the receptor of interest.

Our proprietary »Hitmaster« workstation
Close-up »Hitmaster« workstation

Eucaryotic cells moving inside the microfluidic channel are being aligned by laminar flow. Two separate aqueous phases visible.

Inside the microfluidic chips flow is laminar without any turbulences. This allows for a very predictable transport through microchannels. Both density of targets (droplets, cells, bacteria) as well they speed can be easily calculated.

VERAXA constantly invests considerable resources in the competitive expansion of its know-how in biological assay development for functional assessment of highly relevant complex targets such as membrane receptors (like GPCRs) or life-threatening pathogens. Due to its additional strong roots in technological development, opto-electrical hardware design, software conception and machine integration, VERAXA offers an unmet compilation of screening and assay tools, paired with superior high performance machine automation.

Functional Antibodies

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Anti-Pathogenic Antibodies

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Personalized Antibodies

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Currently, our proprietary »Hitmaster« workstation represents leading benchmark characteristics in:

  • functionality – multiplexed 4 color detection and real time quantitative analysis and sorting,
  • robustness – optimized and shortest optical paths, leading laser hub technology
  • system integration – small functional units, embedded software concept.

Over the last years, VERAXA has developed a superior toolbox for screening and development of:

  • Functional antibodies, are antibodies that exert a modulatory function – either anta- or agonizing – on complex target proteins. Here, VERAXA offers strong assay systems and expertise in assessing anti-GPCR modulating antibodies.
  • Anti-pathogenic antibodies are antibodies that kill or inhibit life threatening bacteria or viruses.

In general, antibodies can interact in different ways with target membrane proteins on reporter cells: they can bind to target receptors or ligands of interest, but only a tiny portion of the binders also induce a modulation of receptor signaling.

VERAXA screens and sorts out only those binders, that have a target receptor associated function on its intra-cellular signaling cascade, either agonistic or antagonistic. Using our unique proprietary and peer reviewed ‘function-first’ technology, we directly measure and quantify reporter cell signals induced by modulating functional antibodies in one single step. By exclusion of target-binding, but non-functional antibodies early on, the number of candidates for characterization and further engineering can be focused on high-potentials, thus reducing time and effort of lead candidate identification.

Sorting via fluorescence

Live-cell calcium flux imaging of cells overexpressing target GPCR which are responding to the activation of the receptor.  Time lapse of 100 s, brightness reflect cytoplasmic Ca 2+ concentration. 

Droplets trapped in microwells on microfluidic chip containing cells of two different populations stained with different marker dyes (green and blue). At lease one of each type is present in each droplet allowing for interactions between two cell types.
Microscopy image off the cellular response to specific ion channel activation. Single cells are labelled for subsequent fluorescence quantification.
Overview of the cell population response to GPCR activation by Calcium flux imaging. Brightness reflect cytoplasmic Ca 2+ concentration.

Images of the cells (stained red with tracker dye) encapsulated in microfluidic droplets together with fluorogenic reporter. After expression of reporter gene the substrate is converted to fluorescent product (green). Intensity of the fluorescence mirrors activation level. For clarity fluorescent intensity is shown in the lower panel with warmer colours representing higher intensity values.

How antibodies interact with target cells

There are several ways, in which antibodies may interact with target cells

Function Up

Functional antibodies may agonize the receptor of interest and increase the related intracellular signaling. During screening, the strength of the intracellular receptor-antibody mediated signal is quantitatively measured in real time and serves as first pass sorting filter.

Functional upregulation could also be caused by antibodies, that act as allosteric enhancers. Here, the binding to membrane receptors induces a conformational change of the target receptor, thus enabling binding of the cognate ligand with greater affinity.

Function Down

The same procedure holds for antagonizing antibodies, i.e. antibodies that may decrease receptor mediated intracellular signal cascades by binding to the receptors and blocking the natural epitope for ligand docking.

Functional receptor antagonism may also be induced by antibodies, that bind to and thus block receptor ligands from their interaction with the receptor.

VERAXA has set up procedures and assays to analyze the relevant fluorescent readout of the intracellular signal cascades within droplets housing a competition mix of B-cell, receptor cell and natural ligand.

No Function

Antibodies can bind to their complementary receptor structure without modulating any intracellular receptor signal cascade (non-functional mAb). Those non-functional binders may however still be inducers of Fc mediated effector function.