ELISA BASICS Enzyme Linked Immunosorbent Assay Food Safety Scientist Curriculum © 2014 Board of Regents, South Dakota State University iGrow.org This project was supported by the USDA NIFA grant number

iGrow.org Introduction of ELISA Introduced by Engvall and Pearlmann in Review the following Basic principles of ELISA Advantages of using ELISA Uses of ELISA widely used © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Basic Principles of ELISA Based on Basic Immunology Response Lock and Key Concept Antigen (Key): substance when introduced into the body produces antibodies Antibody (lock): protein in the body that is used by immune system to identify and neutralize foreign targets (referred to as antigens) Key fits into the lock © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Basic Principles Cont’d. Enzyme conjugate substrates Enzyme that converts colorless substrates to a colored product © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Visualization of ELISA ELISA Graphic Animation: M&feature=relmfu M&feature=relmfu Created by Cary Engleberg of the University of Michigan © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Advantages of ELISA 1. Fast – 90 samples tested in 2-3 hr 2. Sensitivity (up to 10 pg/mL) 3. Specificity (sample with high concentration contaminants 4. Many samples can be processed at once 5. Small sample size required (10 μ L ~ 100 μ L) 6. Colorimetric results – easily observed and measured (spectrophotometer) 7. Test for presence of Ag or Ab 8. Flexible usage for research design 9. Easy to learn, simple procedure © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Lateral Flow Tests Variation of ELISA Test. Paper strips instead of micro test well. Test strip – paper with antibody and colored beads preloaded strategic locations. Test solution flows laterally across paper, eventually reaches antibodies. If the antibody and antigen (i.e. an allergen) bind – color beds are activated. Often a qualitative test – yes or no at a specific level YouTube Graphic Animation Lateral Flow Device: © 2014 Board of Regents, South Dakota State University iGrow.org

iGrow.org Can you identify specific types of test kits for the categories below? Viral Contamination Hormone levels Infections Specific disease factors Drugs Allergens in food Residues in food Toxins in food Others © 2014 Board of Regents, South Dakota State University iGrow.org