Mice, Allergies, & Genetics

Allergies are the sixth leading cause of chronic diseases. Dr. Chris Lantz, an immunologist and professor in JMU's biology department, spoke at EMU last Friday about his research on the causes of allergies using genetically engineered mice.

In a presentation in the Science Center entitled "Allergies, Inflammation, and Parasite Immunity: Studies Using Genetically Engineered Mice," Lantz spoke about two forms of allergic reactions. Local allergic reactions affect a certain part of the body, such as reactions that cause a runny nose; systemic allergic reactions can affect the whole body and are potentially more dangerous.

Lantz discussed the body's reaction to allergens such as pollen. When the body is first exposed to an allergen, it produces antibodies. These antibodies attach to receptor sites on cells, and when the allergen next enters the body, it attaches to the antibody. This causes the cell to release a mediator, such as histamine, which causes the allergic reaction.

To research and study allergies and their causes, Lantz picked the protein Interleukin-3 (IL-3) to study in depth in connection with allergies. In vitro (in an artificial environment outside the body), IL-3 stimulates the growth of three types of cells (mast cells, eosinophils, and basophils) and enhances their function in the body.

To learn more about the function of IL-3 in a living body, Dr. Lantz used mice as test subjects.

Some of these mice, called "knockout" mice, were engineered to lack IL-3. Using a control group of mice that did have IL-3, Lantz and his students exposed both groups to parasites such as nematodes that cause gastrointestinal problems. The mice were monitored to see how long it took them to throw off the infection.

Once the data was recorded, the mice were "sacrificed," as Lantz put it, and the number of mast cells, eosinophils, and basophils were counted. Lantz wanted to see if IL-3 promotes cell growth in vivo (in a living body) as well as in vitro.

In the end, he found that the protein does promote parasite expulsion, and therefore cell growth. In looking at slices of tissue taken before and after the experiment from both groups of mice, Lantz also found a larger number of cells in the non-"knockout" mice after the experiment.

He has concluded that IL-3 is necessary for parasite immunity, but a decrease in contact hypersensitivity reactions (such as allergic reactions that occur after contact with poison ivy) will only happen if IL-3 is suppressed. Lantz continues to do research with the engineered mice and IL-3.