Why do ELISAs yourself when you can
We now offer a unique new service to carry out ligand binding assays powered by ProImmune’s ProArray Ultra® customizable protein microarrays.
Figure 1: ProArray Ultra® ligand binding assays can be produced in line with typical configurations for microtiter plates. Antisera or plasma can be used In place of antibodies and any protein-protein interaction can be explored. Linker or biotin-streptavidin linked formats can also be used. The customer retains the freedom to set up and optimize the assays for their specific purposes.
Additionally, what are your salary costs for standard plate based assays? The fully loaded salary cost (base salary + direct salary overheads) for your technician may be $40,000 per annum and you may expect them to work 1,800 hours per year costing you approximately $22 per hour. A ligand binding assay with, e.g. 100 plates would take about two weeks to perform, analyse and report at a direct technician salary cost of $1,760, costing you $17.60 per plate. The consumables alone could increase this cost to almost $80 per plate. And again this does not account for any further overheads – only direct material and labor cost.
Both Luminex® and MSD® additionally require the purchase of proprietary equipment and software, which also has to be maintained. Furthermore each instrument is clearly limited in its peak capacity and by its physical location. Anyone can use our all-inclusive fixed cost service at any time.
Depending on the assay setup we often match such costs, meaning that you can break-even without taking into account any further overheads, such as equipment, lab-space, supervisory or administration. When you consider these factors, the question becomes not whether you can afford to outsource, but whether you can afford not to.
The ProArray Ultra® technology is appropriate for a range of programs and projects, including:
Screen sera for multiple protein reactivities. If you have access to large scale, historical serum banks 1000s of sera could be screened against dozens of proteins using minimal sample volumes.
Reverse immunology on proteins or entire pathogen proteomes.
Screen sera from disease state or convalescent donors against overlapping peptides.
Cancer, infectious diseases, cardiovascular, metabolic, CNS – your imagination is the limit.
Mapping is linear in the first instance (unless conformational peptides are used), but strong conformational epitopes will be detected in linear sequences too.
The platform also allows for the use of constrained peptides, e.g. cyclized peptides.
Disease progression cycle.
Pathogen life cycle and recovery phases.
For example: ProArray Ultra® was used for measuring release of the cytokine IL-6 in whole blood caused by the therapeutic antibody Campath® in a dose escalation study (see full information on the ProStorm® Cytokine Release Assay here).
ProArray Ultra® has been specifically developed as a combined peptide and protein array platform; combining the epitope/interaction site resolving power of scanning peptide arrays with that of high throughput and protein interaction screening.
ProArray Ultra® achieves full compatibility for overlapping peptide libraries and proteins, and uses a flexible peptide synthesis platform to enable printing of arrays optimized for specific applications. Moreover, our design improvements result in greater uniformity of spot morphology between peptides and proteins, reduced background signal and improved assay performance in terms of sensitivity, dynamic range, and variance.
The result is a protein array platform that is comparable in analytical performance to MSD® technology and that outperforms ECL ELISA assays, while at the same time tens of thousands of interactions can be detected in a single experiment. More importantly, only microliter amounts of sample are required for each analysis, enabling projects using limited amounts of sample that are simply impossible to carry out with 96-well plate-based assays.
The design of ProArray Ultra® overcomes the compromise between the analytical quality of multi-well immunoassay platforms and the scalability of existing protein and peptide array technology. Evaluation of our new design features against other more conventional assay methodologies, such as optimized ECL ELISA and the MSD® technology shows that ProArray Ultra® compares favourably to both plate-based platforms, and has lower background and better overall signal to noise performance (figure 1).
Figure 1: Results of a direct comparison of ProArray Ultra® (blue bars) and high-performance 96-well MSD® assay technology (red bars) for identical peptide libraries derived from the well-characterized Hepatitis B Virus surface Antigen (HBVsAg) incubated with the same anti-HBVsAg seropositive serum sample. All data include error bars reflecting standard error of the mean (SEM) values. ProArray Ultra® compares favourably to both ECL ELISA and the MSD® plate-based platform, and has lower background and better overall signal to noise performance. The peptides identified as epitopes by ProArray Ultra®correlate with results from the MSD® assay.
Figure 2: Limit of Detection (LOD) comparison for MSD® and ProArray Ultra® using a specific monoclonal antibody. A saturation curve profile was obtained with a linear range of approximately 2.5 logs for both ProArray Ultra® and MSD® assay. Very low signal variation was found for both technologies in terms of signal detected. The limit of physical detection can be seen as ~0.5ng/ml.
Our printing technology confers complete flexibility for design around your requirements.
The ProArray Ultra® microarray setup is based on five printing layouts of 1, 2, 4, 8 or 24 identical sub-arrays per slide. The slides can be overlaid with a separation gasket allowing each sub-array to be incubated with an individual antibody-sample, i.e. up to 24 separate samples can be analyzed per slide.
The exact print setup is based on the number of peptides or proteins being probed, the number of sample repeats required, and the number of technical repeats required (at least 3 are suggested, up to 6 are recommended). All these factors are taken into account to create the optimal printing layout. The five different print setups can accommodate a large range of custom printed features (peptides & proteins) alongside standard control spots.
Further detailed technical and performance data (PDF)
Contact us to discuss your project and we will design an assay and array format tailored to achieve your objectives.