What Are the Main Types of Immunogenicity Assays?

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Many scientists turn to immunogenicity assays when faced with the arduous task of eliminating a disease from an organism. Assays are commonly used in the testing and development stages of vaccines. They are used to evaluate how well a vaccine will stimulate an immune response. Immunogenicity assays have also been used in other ways, such as predicting drug efficacy and developing diagnostic tests. The following are the main types of immunogenicity assays.

Enzyme-Linked Immunosorbent Assay

Enzyme-Linked Immunosorbent Assay is a method for detecting the antigen. The antigen molecules are coated around the wells of a glass slide. They are then placed next to the wells’ sample. The antibody is added, and there will be a precipitate, which is detectable underneath using an enzyme. Any molecule that reacts with the antibody will have a colored precipitate. This method has many advantages. It can detect minimal amounts of antigen. The process also requires fewer samples to be tested, and it is inexpensive. This assay can be used on animals or plants, and humans. It has multiple antibodies created through gene amplification methods used in this assay.

Enzyme-Linked Immunofluorescent Assay

Enzyme-Linked ImmunoFluorescent Assay uses fluorescently labeled antibodies with a polymer. The polymer acts as an antigen receptor to detect antigen presence. The method works using a modified ELISA format. Fluorescently stained antibodies are used instead of enzymes to detect bound reactants. This method is proper when studying, detecting, and quantifying antibodies in serum. This assay can detect and quantify antibodies in many serum samples. The fluorescent molecules will not alter the immunoglobulins or produce false-positive results.

Fab’ fragments of immunoglobulin A

The Fab’ fragments of immunoglobulin A (FICA) assay is an enzyme-linked immunosorbent assay. It detects specific antibodies by an antigen-antibody reaction between Fab fragments of IgA and its antibody with the antigen. This is a labeled polyvalent antifungal antibody (PABA). The assay is often referred to as the sputum fungal culture method. It is used to diagnose fungal infections. Samples must be collected and processed within a specified time frame. After processing, the samples are put into wells on a plate. They are treated with a labeled antigen. There will be no reaction if there is insufficient antigen to react with all antigens.

Immuno-radiometric Assay

The immuno-radiometric assay (IRMA) converts the radiolabeled antigen into light using a gamma counter. The amount of radioactivity quantified by the counter represents the number of antigen-antibody complexes present in the sample tested. IRMA is primarily used for the detection of antibodies to HCV and HIV. The assay is conducted using gamma-counting technology. No electrical power or consumable reagents are required. It has no cross-reactivity with other substances, e.g., non-protein antigens. Hence, it is relatively easier to operate and requires a shorter time for the assay.

The Radioimmunoassay

Radioimmunoassay (RIA) is a particular type of immunogenicity technique. It quantifies concentrations of typically small molecules, macromolecules, or dyes. The method is generally distinguished from other forms in the field. It can allow high detection sensitivity. It also preserves sample quality due to an automated process. Therefore, it allows for the most accurate representation of the concentration in a sample. This makes it an appealing method for use with biological samples. RIA is a non-competitive assay. This means it does not directly bind to antigen proteins. In natural immunogenicity assays systems, this type of immune response is expected. The body and bind produce antibodies to antigens in a one-to-one relationship. However, in the case of RIA, it is different. The antibody is bound to a hapten surface called hapten conjugates or a solid phase.

Immunogenicity assays are used in many areas of science. Immunogenicity assays help doctors identify risk factors for developing autoimmune diseases in their patients and prevent them from happening. Immunogens are engineered proteins. They trigger the immune system to produce antibodies against them. The antibody molecules then bind to antigens and block their effects. This prevents the antigen from causing infection or disease.