ELISA is a gold standard bioanalytical technique used in the quantification of several biomolecules such as protein, peptides, hormones, and antibodies. ELISA quantifies biomolecules by measuring the signal intensity produced after the reaction ends. ELISA services and ELISA labs carry out assays for sponsors and large pharmaceutical companies.
ELISA assay validation becomes necessary as large companies often outsource drug development-related studies to clinical research organizations. Thoroughly developed and validated protocols help demonstrate valid bioanalytical results, and therefore once study data are delivered, sponsors usually request all critical protocols carried out during the analysis.
So how does a typical ELISA testing service perform ELISA?
Depending on the detection strategy, ELISA comes in different formats. They can be direct ELISA, indirect ELISA, sandwich ELISA or competitive ELISA. However, all ELISA formats follow three fundamental elements. The first component comprises the coating of the ELISA wells. Antigens are either directly or indirectly immobilized on the polystyrene surface. Immobilization can be achieved either directly by adsorption or indirectly by a capture antibody. The next component is the formation of an antigen-antibody complex. The incubation of the reaction mixture with antibodies that are specific to the antigen results in the formation of the antigen-antibody complex. This complex is needed for signal generation.
The last piece of the puzzle is signal detection. Antigen detection can be direct for enzyme-linked primary antibodies, or in the case of enzyme-linked secondary antibodies, the antigen is detected indirectly. Depending on the type of ELISA, the generated signal is either fluorescence, color change, or chemiluminescence. The generated signal is measured using assay-specific detectors.
ELISA protocols and how to request one?
ELISA testing services conduct assays for a wide range of clinical and non-clinical applications. These studies include pharmacokinetic studies, toxicokinetic studies, immunogenicity testing assays, and cell-based toxicity assays. They perform assays using pre-validated research use only kits or ELISA assays that are developed from scratch. Research use only kits comes with a validated assay protocol supplemented with troubleshooting guidelines. But with newly developed ELISA, assay protocols can get a little tricky.
Sponsors should be aware of the assay specifications when the method is developed from scratch. Before commencing any new assay protocol, sponsors should have an in-depth discussion with scientists at ELISA labs to ensure that the protocol is completely customized according to their requirements. There should be total transparency while collaborating on ELISA development, as an open discussion will help sponsors acquire assay protocols once the study is complete. Along with a quick turnaround and flexibility, procuring assay protocols aids drug approval while maintaining regulatory integrity.
ELISA is increasingly becoming the go-to bioanalytical technique for the detection of several large and small biomolecules. Today, several pharmaceutical and drug developers outsource ELISA assays to boutique ELISA testing service. These services adopt latest technologies and GLP to thoroughly develop and validate ELISA assay, which is the key to the successful approval of drug products. Hence, during technology transfer, ELISA services should efficiently document newly developed ELISA protocols and transfer them to all the concerned parties.