Unlocking the mysteries of the immune system

13 Dec 2018 | Back to News, Publications and Annual Reports

Science has unlocked another clue to the workings of the human immune system. An article just published in leading science journal Nature presents new information about this vital bodily defence system – information that will be instrumental in the search for new therapies like those developed by BPRC.

As human beings, we are all born with an immune system that protects us against pathogens. It's an ingenious and complex defence, and with many therapies for serious illnesses designed to activate our immune system, scientists want to figure out precisely how it works.

How does the immune system work?

Broadly, as follows: almost as soon as you run up an infection, the immune system leaps to your defence, using various means to fight off the pathogen. Crucially, the immune system innately has two distinguishing features. First, it differs (to a greater or lesser extent) from one animal species to another. Second, not every cell in the body reacts to infection the same way.

As such, it is a mystery how this system, with all its variations, is able to work as effectively as it does, since it has to do its job without doing damage to the body it is trying to protect. Eliminating pathogens, in other words, requires a combination of powerful and well-balanced action. Until recently, it was still a mystery how such a powerful system could vary among species while also varying its responses within a single body. Now, science has unlocked part of that mystery.

What have scientists discovered?

A research team examined the tissue and cell response to pathogens across various animal species, comparing mouse, rat and rhesus macaque – from BPRC – amongst others, with human cells. When using animal models in this way, it's crucial that the immune response to a therapy matches that in humans as closely as possible. If a particular immune component exists only in humans and primates, for example, therapies targeting that component can only be tested on primates.

The scientists conducting this study noticed that genes which show little interspecies variation also vary little in the amount of protein they produce. They also found genes that diverge more from one species to another. These latter genes carry out specific tasks in the immune system and are built to be able to rapidly evolve. This ability is key, given that animals, including humans, are in a constant battle with pathogens. Rapid adaptation to mutating pathogens is essential for a species' survival.

Now published in the leading science journal Nature, this study reveals the apparent mechanism whereby, over the course of evolution, animal species have been able to adapt in response to extant pathogens.