Immune system is one of the most important parts of our body that protects us from viruses and bacteria. There are two ways for our immune system to work. First is killing the foreign bodies inside the cell by using reactive oxygen species (ozone, hydrogen peroxide, bleach, etc), which are produced by enzyme NOX2, and the second is killing them outside the cell, using poisonous net composed by DNA called “neutrophil extracellular traps” (NETS).
People thought that the ways of how immune system works was only in human and other complex animals. However, the microbiologists from University of Geneva (UNIGE) discovered that the social amoeba, an unicellular organism, has a similar way of protecting its body from foreign bodies with human. Usually, these microorganisms survive by eating bacteria as a main source of food. When the food runs out, they gather together and make a slug-like mini animal with lots of pores and survive until the wind or other factors to move them to a new place. To make this slug, 20% of the cell sacrifice themselves in order to make the other 80% into pores. However, there is still 1% remaining keeps its phagocytic functions. “This last percentage is made up of cells called “sentinel” cells. They make up the primitive innate immune system of the slug and play the same role as immune cells in animals, “ explains Thierry Soldati, last author of the study.
As explained in the first paragraph, our immune system uses poisonous DNA nets to kill foreign bodies. According to the study of Soldati and his colleagues in Geneva and the Baylor College of Medicine in Houston, Texas, the social ameoba’s immune systems (sentinel cells) can also produce the DNA-based extracellular traps (ETS) to kill foreign bodies.
This study has great impact for the medical study of the diseases related to humman’s immune system, such as leukemia and chronic granulomatous disease (CGD). Patients with CGD are unable to produce normal enzyme NOX2 and therefore, they suffer lots of diseases even though they are easy to be cured because their immune systme cannot work properly. Now, by modifying and changing the DNA of this microrganism, scientists can do all kinds of experiments that can be adapted to human beings more easily. Thus, by using Dictyostelium discoideum (scientific name of the slug) to find the genetic disorder in immune systmem, scientist will be able to open a new way to find the treatment.