All living organisms have pathogens. As a result, almost all organisms have evolved some form of immune system. The human immune response is one of the most complex biological systems that we know of, but the deeper we look, the more we discover remarkable examples of immunity in other organisms too.
In this series, we examine the full spectrum of life on Earth and ask what drives immunity, why it sometimes goes wrong, and how might we use natural immune processes to help protect ourselves, our technology and even our society from harm.