ELISA is based on the specific interaction between an antigen and an antibody. It uses an enzyme as a marker to generate a detectable signal, often a color, which is proportional to the amount of the targeted substance present in the sample. ELISA is widely used for its sensitivity, specificity, and ability to analyze a large number of samples simultaneously.
Our expertise in ELISA
At BioSellal, our team of experts is dedicated to the development, optimization, and validation of ELISA kits to meet today's diagnostic needs. Our ELISA reagents are designed to offer both sensitive and specific detection of antibodies to pathogens of interest in different animal species. These diagnostic tools are essential for the control of infectious diseases in herds.
Our kits are validated to French standards U47-310 and U47-019 (AFNOR).
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PRACTICAL
Our ELISA reagents are ready-to-use and colored for easy distinction. Our kits are single-pack and in breakable strips.
RAPIDITY
We offer short incubation protocols for most of our ELISA reagents.
RELIABILITY
We offer a tracer sample for each application to ensure the quality of your results.
To improve the monitoring of our results over time, we suggest the use of ready-to-use low-positive tracer samples (MRI, internal reference material). This makes it possible to monitor the reliability of the test using a control card. It is recommended to use one for each test.
To find out more about our ELISA applications and diagnostic solutions, please contact us.
About ELISA
PRINCIPLE OF INDIRECT ELISA
This technique enables the detection and quantification of specific antibodies against a given antigen in a sample, by exploiting the specificity of antigen-antibody interactions and labeled secondary antibodies. The main steps are as follows:
➜ Immobilizing the antigen: First, the wells of a microtiter plate are coated with a specific antigen. This antigen is the one against which the antibodies you wish to detect are directed. After immobilization, the wells are washed to remove excess unbound antigens.
➜ Blocking: To prevent non-specific reactions, a blocking solution is added to cover non-specific binding sites on the well surface.
➜ Incubation with sample: A sample containing potential antibodies (patient serum, for example) is added to the wells. If antigen-targeting antibodies are present, they will bind to the immobilized antigen.
➜ Washing: Wells are washed to remove all unbound sample components, including antibodies that do not recognize the antigen.
➜ Antibody detection: a second antibody, known as a "detection antibody", is added, which is specific to the type of antibody present in the sample (for example, anti-human IgG if we're looking for human IgG). This detection antibody is conjugated to an enzyme.
➜ Wash: A new wash is performed to remove any unbound detection antibodies.
➜ Enzyme substrate: A substrate is added which reacts with the enzyme conjugated to the detection antibody. This reaction produces a color change or fluorescence that can be measured.
➜ Measurement: Optical reading is performed using a plate reader. The intensity of the color or fluorescence measured is proportional to the amount of specific antibody present in the sample.
PRINCIPLE OFCOMPETITIONELISA
In competition ELISA for antibody detection, the aim is to measure the presence and quantity of specific antibodies in a sample by assessing their ability to compete with a reference antibody for binding to a common antigen. Here are the main steps:
➜ Antigen immobilization: The target antigen is immobilized in the wells of an ELISA plate.
➜ Blocking: Wells are treated with a blocking solution to reduce non-specific interactions.
➜ Incubation with sample and labeled antibody: A mixture of the test sample (which potentially contains the competing antibodies) and an antibody specific to the labeled antigen (usually with an enzyme or fluorophore) is added to the wells. The antibodies in the sample and the labeled antibody will compete for binding to the immobilized antigen.
➜ Washing: After incubation, a wash is performed to remove unbound antibodies and excess labeled antibody.
➜ Detection: A substrate suitable for the enzyme conjugated to the labeled antibody is added. The reaction between enzyme and substrate generates a detectable signal (color change, fluorescence, etc.).
➜ Measurement: Signal intensity is measured. High signal intensity indicates low competition from antibodies in the sample (fewer specific antibodies in the sample), while low signal intensity indicates high competition (more specific antibodies present).