Evidence Shows the Immune System Adapts to Parasites

While parasites are commonly regarded as nothing more than little wrong-doers, which can actually harm you a lot, a new scientific study comes to show that this is not always the case. According to a research published in the June 8th issue of the Journal of Experimental Medicine, it may be that parasites were partially responsible for turning certain proteins in our immune system into the inflammatory cell destroyers they are now. Without their help, we would now probably be vulnerable to a large number of pathogens, each more dangerous than the other. Still, parasites also left behind the potential for mutations, which is not always a good one, at least when we think about cancer.

Single nucleotide polymorphisms (SNPs) are the main forms of mutations that parasites leave embedded in our DNA strands after an attack. In order to make sure that more complex mutations, such as multiple SNPs, go on undisturbed, certain genes, which are otherwise employed in the immune system, may become even more aggressive when fighting invading pathogens than ever before. The more these genes are stimulated, the faster and swifter the body's reaction to other infections is.

Researcher Matteo Fumagalli, the leader of the team that published the recent study, browsed over 1,000 SNPs belonging to about 1,000 people worldwide, looking for mutations in genes that coded for immune proteins called interleukins. He learned that, from 91 different types of genes the team found, 44 were already mutated through evolutionary selection, which meant that these genes didn't change due to chance, or because the individual carrying them moved to a new environment.

Additionally, the team also found that, in people with larger amounts of parasites, the diversity of mutated genes far exceeded the human average. They concluded that, over the course of history, exposure to different types of parasites caused the human immune system to become terribly good at defending itself against an enormous array of pathogens. Undoubtedly, over the course of history, each of the viruses, bacteria or microbes our immune system can now kill claimed hundreds and thousands of victims, until our bodies learned to cope with them.