Reader question: What was the immune system for?

A while back, a reader asked me this interesting set of questions:
Did Adam and Eve need their immune system before the fall?  If they didn't, then was it pre-designed just for the post-fall world? Or was it created after the fall?  If they did need it, what for? Were there natural evils for which they needed immunity? Will there be these evils also after the resurrection?
I don't know about after the resurrection, but I've thought a lot about before the Fall.  It's a lot more complicated than you might think, mostly because of our expectations.

Today we live in a world dominated by the germ theory of disease, which works very, very well.  The idea is that specific infectious diseases are caused by specific agents: microbes, bacteria, viruses, what the public calls "germs."  An example I mentioned last week is cholera, which is caused by Vibrio cholerae, which is transmitted through contaminated water.  Other examples might be malaria, which is caused by a microorganism called Plasmodium, and AIDS, which is caused by HIV.  There are specific criteria that must be met in order to conclude that a particular set of symptoms (the "disease") is caused by a specific organism (the "pathogen"), which is how scientists are confident that infectious diseases can be linked to pathogens.

The immune system is the part of our body that is supposed to ward off infections.  It's an amazing set of cells and organs that can detect alien things in our bodies and dispatch them.  My favorite is the Membrane Attack Complex of the complement system, which basically pokes holes in bacteria and causes them to blow up.  No, I'm not kidding.  It's technically called osmotic lysis, but that just means that the bacterium blows up.

Such an amazing set of structures and biochemistry immediately calls to mind creationist arguments for design.  In other words, the immune system is an amazing design, but that presents an interesting problem.  If there was no disease before the Fall, which is something creationists like me believe, then what was the immune system doing?  If there were no pathogens, then what's the point of an immune system?

To answer this question, let's go back to the germ theory of disease again.  First of all, it works.  That's certain, but it's not the whole story.  There are other things in our world, other microbes in our systems, that are not germs.  In fact, after talking to microbiologists, I get the impression that the vast majority of microbes out there are not germs.  They're just there, doing their thing, not bothering anybody.  Some might even be helping us by making nutrients accessible to us or by controlling pathogenic microbes that might otherwise make us sick.  Our gut bacteria are a good example.  The microbes living in our intestines provide important metabolic functions for us (see this paper for more info), and they are not what we usually think of as "germs."

Contrast that reality with the average person's concept of bacteria today.  Everywhere we go in the developed world, we're encouraged to live an antiseptic lifestyle, with hand sanitizers and antibiotics and even antibacterial soap.  We have a cultural misconception that all microbes are bad, and therefore we should kill them ALL, which might be causing more problems than it helps.  Certainly the rise of antibiotic resistance in real pathogens has been very alarming, and it's attributable to the overuse of antibiotics.

So there's more to the microbial world than pathogens, and there's probably more to the immune system than just fighting them.  Joe Francis has argued that the immune system is just as important for allowing good things in as it is for keeping bad things out.  Another possibility is that the immune system was intended to keep microbes in their appropriate places.  That would assume that infectious disease is largely due to microbes moving into environments they weren't supposed to move into, which implies that the immune system is the thing that's gone wrong, not the microbes.  There are other, more well-known failures of the immune system, like allergies, so a faulty immune system isn't some wild speculation.

So there are lots of possibilities and lots of areas to explore to understand the function of a pre-Fall immune system.  In the mean time, we should all ease up on the antibacterial soap.  You can't imagine how many friends you're slaughtering with that stuff.

Feedback? Email me at toddcharleswood [at] gmail [dot] com.