Antibodies/Antigens: ELISA Theory

The video tutorial by Kevin Tokov explains the Enzyme-Linked Immunosorbent Assay (ELISA) process, focusing on its application in detecting specific antigens using antibodies. It covers the specificity of antibodies, the role of primary and secondary antibodies, and the importance of blocking proteins. The tutorial also discusses the use of enzymes attached to secondary antibodies to produce measurable products, which can be analyzed using spectrophotometry. The video concludes with a brief introduction to the Western blot technique.

What is the primary role of antibodies in the immune system?

• To transport oxygen in the blood

• To bind to antigens and elicit an immune response

• To store genetic information

• To break down food in the digestive system

In an ELISA test, what is the main purpose of using a plate with antigens?

• To increase the temperature of the reaction

• To provide a surface for antibodies to bind

• To measure the pH of a solution

• To act as a catalyst in the reaction

Why is it important for the primary antibody in an ELISA to be specific to one antigen?

• To allow it to change color

• To make it dissolve in water

• To prevent it from binding to non-target antigens

• To ensure it binds to all antigens present

What is a key requirement for the secondary antibody used in ELISA?

• It must be colorless

• It must be from a different species than the primary antibody

• It must be from the same species as the primary antibody

• It must be able to bind to any antigen

How are enzymes attached to antibodies in an ELISA test?

• Covalently linked in a laboratory

• Naturally occurring in the body

• Through magnetic attraction

• By dissolving in water

What is the purpose of the enzyme attached to the secondary antibody in ELISA?

• To increase the temperature of the reaction

• To dissolve the primary antibody

• To catalyze a reaction that produces a measurable product

• To change the color of the antigen

In ELISA, what does a higher intensity of color indicate?

• A lower concentration of antigen

• A higher concentration of antigen

• No antigen present

• A neutral pH level

How can you quantitatively determine the amount of antigen in an ELISA test?

• By observing the size of the plate

• By counting the number of antibodies

• By using a UV-Vis spectrophotometer to measure absorbance

• By measuring the temperature

What is a potential downside of using spectrophotometry in ELISA?

• It cannot measure absorbance

• It is slower than some proprietary machines

• It requires a large sample size

• It is less accurate than other methods

What is the main advantage of using a spectrophotometer in ELISA?

• It is less expensive

• It can measure temperature

• It provides more accurate measurements

• It is faster than other methods