In early life, one is exposed to thousands upon thousands of microorganisms. The most affected organs are naturally the gastrointestinal tract and the lungs, as they are constantly exposed to the outside world. How one is affected via microbial exposure during this early stage of life could have an effect on them throughout their life. This article discusses the benefits of these early exposures to microorganisms in the way of preventing diseases later on.

An important player for protecting the body is a cell known as the Invariant natural killer T cell (iNKT). In this article they explained their expiriments on 8 week old mice,  where they were subjected to two environments, one germ free (GF) and the other specific pathogen free (SPF). When tests were taken to find the difference in number of iNKT cells between young GF mice and SPF mice, they found that the GF mice had lower numbers of iNKT cells in the majority of their gastrointestinal tract as compared to the SPF mice. A second test was then conducted to see if they could increase the number of iNKT cells in adult GF mice to a normal level. But when the GF mice were exposed to SPF conditions they did not restore iNKT cells to a level similar to the SPF mice. They concluded that since the GF mice were restricted exposure to microbes at an early age that its affect lasted into adulthood.

To take the test further they exposed pregnant GF mice just before delivery with SPF colonies. The offspring had a number of iNKT cells similar to the SPF mice, showing that early exposure does have a very powerful impact on the body’s response to microorganisms. But in the absence of microbes at the beginning stages of life and then upon later exposure, the cells will be stimulated and produce and auto-inflammatory response. The researchers also state that this information may be applicable to humans as there are extensive similarities between mice and humans.