Was the immune system designed or a big accident?
The immune system is actually an astonishing array of structures and mechanisms designed to defend us from a wide variety of agents, including bacteria and viruses. The mechanisms, in turn, can be grouped into two complementary systems. The first mobilizes an attack on invading microbes within hours. The second takes several days to respond but targets the invaders like a well-aimed arrow. This second system also has a good memory, so that if a specific invader returns years later, this enemy will be met with a rapid response. The whole system works so well that often you do not even realize that you have been infected and effectively defended. Also amazing is the way the immune system distinguishes between foreign substances and the hundreds of cell types that make up our body.
Microbes sneak in through our breath, our food, our urogenital tract, or breaks in our skin. When the immune system detects intruders, it sets in motion a cascade of reactions involving dozens of precisely designed proteins. Each component in this cascade activates the next to amplify the counterattack. The process is mind-boggling!
What do you think, was the immune system designed or did it come about on its own?