http://ocm.auburn.edu/newsroom/news_articles/2017/06/auburn-university-scientists-make-breakthrough-discovery-on-the-evolution-of-the-innate-immune-system.htm
Tassia and the team in the Halanych lab studied genetic datasets of more than 40 different deuterostome species including human and invertebrate. The research showed evidence that humans and other deuterostomes share a common evolutionary history of their innate immune systems.
"Humans and other vertebrates possess two types of immune systems–innate and adaptive," said Tassia. "The adaptive immune system is the one we are more familiar with. It contains components such as antibodies that allow for 'immunological memory,' which is why immunizations are an effective tool against diseases and pathogens. Whereas the adaptive immune system must 'learn' to recognize a pathogen, the innate immune system is prepared from the get-go. The innate immune system relies on a suite of molecules called 'pattern-recognition receptors' which, over long periods of evolution, have adapted to recognize common molecular patterns associated with bacteria, fungi and viruses. So, if bacteria like E. coli get into somewhere they shouldn't, such as a really nasty paper cut, cells in your body sporting these pattern-recognition receptors are ready to mount a rapid immune response, causing inflammation, recruiting more immune cells and destroying those bacteria."
Tassia explained that the adaptive immune system is exclusive to vertebrates. Components of the innate immune system, on the other hand, predate vertebrates and are present in groups as old as jellies, whose last common ancestor with vertebrates existed more than 500 million years ago. As a result, he began his work by comparing the most well-known pattern-recognition receptors, "Toll-like receptors," or TLRs, from more than 40 different invertebrate and vertebrate species.
