12: Biotechnology and Immunology
- Page ID
- 107297
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Learning Objectives
- Define seroconversion.
- State the importance of rapid and accurate diagnosis of infectious diseases.
- Differentiate between antigens and antibodies.
- Identify the role of antigens and antibodies in developing pathogen detection assays.
- Describe the main components of the lateral flow immunoassay (LFIA).
- Identify the importance of controls in LFIAs.
- Apply knowledge of LFIAs to detect COVID-19.
The rapid and accurate diagnosis of infectious disease is often crucial to determining patient treatment, supportive care, and precautions for the health care worker. However, some infectious diseases are more easily diagnosed than others. For example, although many types of bacteria may be easily identified by appearance on differential media, gram staining, metabolic testing, etc.… these identification methods may be time-consuming and are not always practical. In addition, not all pathogens (e.g., viruses) can be cultured in the laboratory, and so other types of diagnostic tests are necessary.
Our immune systems respond to the presence of antigens (a foreign substance that stimulates an immune response) by producing antibodies (globular proteins produced and secreted by B lymphocytes) that bind specifically to them. Many diagnostic tests take advantage of the specificity of antigen-antibody binding to detect exposure to a particular pathogen. For example, some diagnostic tests detect antibodies in a patient’s serum- their presence indicates exposure to a specific pathogen, as these antibodies will only be present if the patient has been exposed to that pathogen. Other diagnostic tests may look for specific antigens in serum (or in a cultured clinical sample) by reacting them with known antibodies in clinical laboratory tests.
In this lab, you will learn how to use a standard immunological test—a rapid lateral flow immunoassay that detects serum antibodies to diagnose infectious disease.
COVID-19 IgG/IgM Rapid Test Cassette (While Blood/Serum/Plasma)
Read THE FIRST TWO (2) PAGES from the In Vitro Diagnostic Medical Device Emergency Use Authorization document submitted to the FDA for the COVID-19 IgG/IgM Rapid Test Cassette:
https://www.fda.gov/media/138438/download
Note: This is a highly technical, government document that is required for submission and acceptance by the FDA for use of novel diagnostic medical devices. Industry biotechnology companies must undergo thorough evaluation by the FDA before these devices are released for public use, which is why this document contains several pages of rigorous scientific testing and outcomes. I want to underscore that you are only required to read the FIRST TWO (2) PAGES of this document.
Procedure:
LAB ASSIGNMENT
1. What were the results of your test? Explain what that means in terms of presence of antibodies.
2. Explain how the RightSign COVID-19 IgG/IgM Rapid Test works. Include in your answer the following vocabulary: Whole blood/serum/plasma, anti-human IgM antibody, anti-human IgG, anti-rabbit IgG, gold conjugated COVID-19 antigens.
3. What is the purpose of the anti-rabbit IgG?
4. True or False: The test performed during this lab detects the presence of COVID-19 antigens in the blood.
5. This test utilizes recombinant COVID-19 antigens (multiple antigens combined to make 1 antigen) which are then conjugated to colloid gold (the antigen is chemically combined with colloid gold). What is the importance of using recombinant antigens and colloid gold as a conjugate?