Students will be able to: Describe the structure and function of antibodies in the body and the applications for antibodies in biotechnology.

At Sanford Research, scientists need tools to investigate different phenomena and test hypotheses. One tool that is used frequently is the antibody. Although its role in the immune system is vast and important, its use as a tool for research has helped to open new doors to the understanding of the inner workings of the cell.

Teacher preparation:

Start by printing out the Exploring Antibody Applications Student Journal, Exploring Antigen Testing Student Guide, and Antibody Coloring Activity. Next, read through the Exploring Antigen Testing Teacher Guide to prepare for a short experiment to start off the lesson.

Use the Exploring Antibody Applications Slide Show to guide you through the lesson.

Part 1
Phenomenon:
Start by asking students what they know about antigen detection kits like the one pictured on the first slide. Students should answer the questions in a think-pair-share model. First, ask students to write about what they know for 2 minutes. Next, ask students to share their ideas with a shoulder partner. Finally, have a discussion as a class about their answers to the questions.

Engage:
Complete the Exploring Antigen Testing experiment. This experiment explores the concept of lateral flow and capillary action. As students complete this activity, they should understand how liquid gets pulled through an antigen test.

Teacher note: Capillary action is the process where liquid flows through a medium without an external force, often against gravity. The lateral flow test uses capillary action to move the liquid through the test strip where it reacts with antibodies positioned along the strip. Capillary action is also used by xylem in plants to move water upward to the leaves. This is a good inter-subject connection to make.

Explore:
Slides 4-9: Ask students to fill out the K and W sections of the KWL chart in the Exploring Antibody Applications Student Journal. They will fill out the L section at the end of the lesson. Antigens are molecules recognized by your immune system. Antigens can be found on the surface of pathogens or allergens. They are also found on our own body cells. Each antigen has a unique structure called the epitope, which is where an antibody can bind to it. The immune system, specifically B-cells, produces antibodies to bind to antigens. Antibodies are also known as Immunoglobulins. There are five types that each have a different production mechanism and function. However, it is important to note that antibodies are specifically generated for each antigen and are specific in their binding capacity.

In this lesson, students will explore the structure of IgG, an antibody that is made by B cells to bind foreign antigens. Antibodies are proteins that contain different segments. The main frame is made up of heavy chains of polypeptides. Along the outside of the Y- arms of an antibody are light chains of polypeptides. At the end of these chains, there are hypervariable loops. The sequence of amino acids and their chemical properties are what create an antigen binding site. Antigens will lock into these regions. 

Print out the Antibody Specificity Coloring Activity for every student. Using colored pencils, ask each student to create a unique pattern of colors and shapes. Have them color in the two variable regions and two antigens with this pattern. All four sections should be the same pattern, but they should be different from their neighbor’s pattern. Ask students to cut on the dotted lines, cutting out the antibody and both antigens. Collect the antigens and antibodies. Take the antigens and scatter them around the classroom or throughout a space like a hallway. Give each student an antibody (it shouldn’t be the one they made). Next, ask students to go find the two antigens that match their antibodies and tape them to the variable regions.

Part II
Explain
Slides 10-14: This section explains the function of antibodies. The immune response is a complicated system and should be explored further, however, as this lesson is focusing on the use of antibodies as tools we will skim over the immune system. Antibodies typically respond to an antigen and either bind them up for destruction or neutralize their ability to invade and destroy cells. Our immune system is not perfect though. Sometimes our own antibodies target our host cell antigens. These autoantibodies (auto=self) can cause many different autoimmune diseases like type 1 diabetes, celiac disease, and lupus. 

We can use the antibody response to our advantage, and this is the purpose of vaccines. A vaccine is a piece of viral protein or even the mRNA for a protein that is injected into the host. The immune system produces antibodies as an initial response and creates memory cells to remember the infection. Antibody levels within blood serum are an easy way to check if someone has been exposed to a particular antigen.

Expand
In a research lab like those found at Sanford Research, antibodies are used daily as tools. In the video, Exploring Antibody Applications, antibody use in microscopy, cell sorting, and clinical diagnostics is discussed. Have students watch this video and summarize each section. (This video is 12 minutes long) Monoclonal antibodies also play a role in cancer research and treatment. The field of immunotherapy is rapidly advancing with antibodies playing a large part in the fight against cancer. Check out this video to learn more. Note that many clinical trials are underway that use monoclonal antibodies. A search of scientific literature would be a good way for students to understand the current state of immunotherapy and the complexity of scientific research. Treatments that end in -mAb are monoclonal antibodies.

Evaluate
Given what students have learned about antibodies, ask students to spend some time doing their own research on lateral flow antigen kits. They should be able to answer the questions on slide 16. Click here for a video explanation of how lateral flow kits work. To finish this lesson, ask students to return to the L section of the KWL chart and fill in what they learned.

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