Into the wild: digging at immunology's evolutionary roots.

The two pillars of modern immunology have been man and mouse; in both settings, investigators seek to reduce complexity and control environmental conditions. However, the world outside the laboratory is immensely variable; this is not 'noise' but represents the genetic and environmental framework in which the immune system evolved and functions. Placing the ever-growing understanding of immunological mechanisms in wider real-world contexts is a massive but fundamentally important challenge.