Life ScienceDiagnostic with peptide arrays

Several diseases are difficult to diagnose when there is a poor number of specific clinical markers or physical symptoms. This is the case of the actual Covid19 pandemic. According to the Pasteur Institute, 30 to 60% of infected people show an asymptomatic form of the disease, specifically for young people. To deal with virus transmission, it is necessary to identify these positive cases. Serological tests can help diagnostic procedures and epidemiological surveillance by identifying positive cases of infection, even for asymptomatic forms of a disease.


Diagnosis with serological tests

Tools to identify patient infection background

The Medical Subject heading (MeSH) defines serological tests as diagnostic procedures involving antibodies reactions. These tests identify the pathogen exposition of an individual by examining its serum composition. The serum is a body fluid derived from blood which contains proteins such as antibodies. The latter are the main actors of the immune system as they interact with antigens, the specific peptide sequences of a pathogen. By analyzing antibody-antigen interactions, one can determine if the patient has developed an immune response against pathogens involved in an infectious disease.

Lack of sensitivity and specificity for conventional methods

To detect antibody-antigen interactions, several methods exist such as ELISA or immunofluorescence assays. These conventional immunoassays are convenient as serological tests because they are fast, easy to perform and non-expensive. However, for some diseases they have insufficient sensitivity or specificity with cross-reactive biomarkers that can mislead the diagnosis.


Improvement of diagnosis with peptide arrays

Identification of  specific biomarkers

Novel biomarkers discovery could help for the development of accurate and high-throughput diagnosis tools, especially for diseases without specific serological tests. As epitopes are well-defined regions of an antigen specifically recognized by antibodies, these sequences are more specific than the entire antigen. Thus, epitope mapping is interesting for the development of specific and accurate serological tests. According to the Medical Subjects Headings (MeSH), epitope mapping gathers the different methods used for the study of antibody-epitope interactions. One of these methodologies is peptide array.

Indeed, this is an attractive method since it allows a high throughput analysis of thousands of epitope-antibody interactions in a single experience. Thus, it enables the discovery of epitopes that can be used as highly specific biomarkers for serological tests. To determine the accurate sequences of these biomarkers, detection methods identify the interactions between antibodies from patient samples and the peptides on the array.

Refinement of analysis with fluorescence detection

In comparison to other methods, peptide arrays with fluorescence detection enable an efficient analysis by decreasing the quantity of samples and reagents needed. InnoScan, Innopsys scanners, are valuable tools for microarray fluorescence detection. Researchers use the InnoScan range for its versatility and scan rapidity that increases peptide arrays potential. InnoScan 710-IR employs infrared detection to improve sensitivity and decrease support background. Meanwhile, high resolution analysis of high-density peptide arrays is possible with InnoScan 1100.


Therefore, peptide arrays combined with Innopsys scanner technology are a powerful tool for serological test development. The identification of novel biomarkers could lead to accurate diagnoses and disease monitoring that were not possible before.