Mission: Bahama
An HIV Detection Simulation Activity

Developed by: Laura Cox, Julie Ertman, Karen Swain, and Larry Wegmann
© American Association of Immunologists 1996

Focus
Immunology is the study of the body's defense system. This curriculum introduces the principles of immunology and AIDS. This exercise uses a hemagglutination technique as a quantitative test for HIV that visually illustrates the antigen-antibody reaction. The laboratory procedure is a test for the presence of an unknown amount of HIV antigen, although simulated reagents are used throughout that are hazard free.

Description
The hemagglutination technique used will simulate a test for the presence of HIV in the bloodstream. NEITHER HIV NOR HUMAN BLOOD PRODUCTS NOR ANY HAZARDOUS MATERIALS ARE USED AT ANY TIME DURING THIS SIMULATION, and, thus, there are no risks involved. The students' role in this exercise are to:

1. screen volunteers for the presence of H IV infection and
2. test the preliminary findings of new combinations of drug therapy on HIV levels in the blood.

This assay is used to illustrate that even with limited resources one can perform a sensitive quantitative test for HIV screening instead of the more complex but commonly used ELISA test.

Curriculum Content
This lesson can be used in any high school biology, general biology or advanced biology course to teach the fundamental aspects of immunology, immunological based diseases, antigen-antibody interactions, and agglutination.

Prior Knowledge
Students need basic laboratory skills. They also need to be familiar with the following concepts: antigens, antibodies, precipitation, agglutination and positive & negative controls. (Those in italics are covered in the Immunology Background section.)

Objectives
Upon completion of this lesson, students should be able to:

1. Explain the need for positive and negative controls in an experiment.
2. Define the essential vocabulary related to this unit from the list provided, and use those words in context.
3. Analyze experimental results.
4. Describe hemagglutination.
5. Discuss the nature of the antigen-antibody complex as it applies to the formation of a mat or button.
6. State the relationship between exposure to a given antigen and the presence of its specific antibody.

Suggested Timeline
Teacher preparation: about 2 hours
Laboratories and Instruction: about 3 days

Materials Needed

• Fine-tip polyethylene transfer pipet
• Large bulb pipette standard tip
• 96 well multiwell plates (u-shaped bottom)
• 1.5 ml microfuge tubes
• Phosphate buffer saline (PBS)
• solutions pH6.4 and pH 7.2

Option 1

• Dulbecco’s PBS

Option 2

• Manually prepare the solutions
• 10 mg Rabbit IgG (technical grade)
• 10 ml Sheep red blood cells, tanned
• (Tanned SRBC is an absolute requirement)
• 2 ml Goat anti rabbit IgG whole serum

Store the sheep red blood cells, rabbit IgG and goat anti-rabbit IgG at 0-4°C as soon as received and on ice during the lab period!

The following are items assumed to be available:

• microcentrifuge
• 37°C water bath