The battle against pathogens

I got to wondering, "Does an infection have an effect on PD?"

Answer - It does and in the future, down the road a piece, I will explain it to you.  But, not now.  You see, in my readings I learned much about the immune system.  Logic dictated that I become acquainted with the immune system so I wouldn't be blown away with jargon when it comes to PD and infections.  How does the immune system fight infections in a PWD.  I never got around to that.  I was stymied by another, more fundamental issue.

 "Is there a god?"

I will tackle that subject later.

Let us first look at the immune system from a beginner's viewpoint.  The immune system is our army in the defense of our body.  Invaders, known collectively as pathogens, attack the body, and we counter-attack with some sophisticated weapons which we will use if the invaders breach our first line of defense, the physical barriers whose jobs are to keep pathogens out of our bodies.

The invader must get around the physical defenses, structures and chemicals which block the pathogen's invasion. Our skin is the primary blocker, but there are others; for example, mucus in the nose that keeps the pathogen in place until, for example, you sneeze.  

When a pathogen (virus, bacteria, micro-organisms eg)  finds an opening, it launches an invasion.  Enter the C cells also known as the leukocytes.  There are several types of leukocytes.  They are our army.  Our "grunts" so to speak.

Let's look at a couple of those grunts at work.  Macrophages and neutrophils are the body's sentries/fighters.  The neutrophils patrol in the bloodstream, as do the macrophages but, as I understand it, the neutrophils are restricted to the bloodstream while the macrophage can get out of the stream and move in the spaces between body cells.  When these leukocytes recognize the presence of a pathogen, they move to the entry site sending out a chemical call to arms and other leukocytes join in the battle,  their aim is to destroy the invaders, which, when they succeed, they "eat" the remains of the dead invader.

The next defenders are the lymphocytes, the T-cells and the B-cells.  B-cells produce antibodies, a protein found on the surface of the defending cell which recognizes antigens on the surface of the invader cell(an antigen is a molecule that attracts an immune response). These antibodies bind to the invader's antigen, marking it for destruction by the body's leukocytes.  

T-cells know the structure of the antigens on your own cells.  If a pathogen is successful in entering a cell (as a virus does to take over the cell and use it to make duplicates of itself) the action of the pathogen can cause a change in the host cell's antigen. This change in antigen is recognized by the T-cell and it removes the infected host from the battlefield.

 Read all about it from the dozens of websites online. There is so much more to the immune system, some of it is beyond me. So, I will stop here and lay me down to think a while.  

The Immune system is so complex, I have to ask "could such complexity be the happen-stance result of natural selection?  Does religion have the answer?  I know it will ave AN answer but will I be able to see it, clouded as it is by the various beliefs, or is the nod to religion in Star Wars more likely, more believable?

I dunno.

May the force be with you.