- Gas Chromatography / Mass Spectrometry
- Flow Cytometry
- Lab Tours
- Classroom Support
As you learned, one of the jobs of the immune system is to destroy any mutated cells which can develop into tumor cells. To understand how dioxin affects this part of the immune system, mice were injected with mouse tumor cells, and some mice were exposed to dioxin just before they were injected with tumor cells.
In this experiment, you will be investigating the effect of one specific dioxin, TCDD , which will be referred to as “dioxin.”
|You will be analyzing mouse tissue samples with the flow cytometer. Specifically, you will be using the flow cytometer to determine the number of cytotoxic T lymphocytes (CTLs) that are present in the tissue. CTLs are a variety of a larger category of lymphocytes called CD8+ T-cells.||
When tumor cells are injected into the body or if a spontaneous mutation occurs, large numbers of CTLs are produced by the immune system. The CTLs are able to recognize the tumor cells and to kill them before they can increase to a large number that would cause the mice to die.
This experiment involves three groups of mice:
After you analyze the samples on the flow cytometer, you will take a look at the data to see how the immune system responds to the tumor cells and how dioxin affects the immune response of the mice.
You prepare the tissue sample in liquid to gently break it into individual cells. Next you add fluorescent markers. Each type of marker binds to one specific protein on the outside of cells. These markers are tagged with fluorochromes (FLOOR-oh-krohms), a type of molecule that emits a specific color of light when exposed to light from a laser.
|For this experiment, you will use two types of fluorochromes to bind to two different proteins on the CTLs in order to differentiate them from other cells. One fluorochrome will emit red light and the other blue light. We will call the two different proteins to which these fluorochromes attach Protein B and Protein R (for the blue and red fluorochromes).|
CTLs have a high amount of Protein B on their surface, but low amounts of Protein R. So, using the flow cytometer, you will be looking for the cells that have many blue fluorochromes attached with very few red fluorochromes attached. You will learn how to analyze the data in the next section.
The sample is now ready to be analyzed on the flow cytometer. Let’s see how the instrument works.
How Does the Flow Cytometer Work?