Monday, March 23, 2015

BASIC IMMUNITY


There is a lot of controversy around vaccinations.  There is a tendency to create separation and “camps.”  Those that vaccinate.  Those that don’t.  The “anti-vaxers,” the “non-vaxers,” the “pro-vaxers.”  Research, life experience, informed discussions, negative talk, judgements, ignorance, fear, guilt, shame...you name it.  It is all part of the  current conversation around vaccination.  

The conversation I would love to have, the one that I think should be the basic foundation of any vaccine discussion, is not necessarily about vaccinations at all.  The foundation, to me, starts with the immune system.  

How it works.  
Why it works.  
What it does.  
How to support it.  
How to nourish it. 

Then the discussion can lead to vaccinations: what they do, how they are introduced to the body, how that effects the immune system, long term immunity vs short term immunity, Th1 vs Th2 immunity, first/second/third lines of defense... etc.  Then we can have a true, informed discussion about physiology, pathology, immunity, and the role that vaccinations play.

The purpose of our immune system is to recognize invading pathogens, prevent their spread, and ultimately clear them from our body.  Our basic immunity has 3 lines of defense that our bodies use to fight off pathogens.   

THE FIRST LINE OF DEFENSE

The first line of defense involves natural barriers: our skin and the mucosal linings in our respiratory, gastrointestinal and urogenital tracts. The skin forms a tough, impenetrable barrier formed by layers of keratinized cells. The internal surfaces are specialized for interaction and communication with their environment and are more vulnerable to pathogens.  The cilia in the lungs, the acid in the stomach and the urogential tract, and the mucus in the gastrointestinal tract all help to create a barrier from invading pathogens.  One specific enzyme, lysozyme, that is secreted in tears, sweat, and saliva breaks down the cell wall of the invading pathogens.   

The cell wall is the brain AND the protective barrier of any pathogen.  Breaking down the cell wall of the pathogen allows the rest of the immune system to render the pathogen null and void.  Without this essential step, the pathogen can reek havoc on our immune system and our body. 

If there is a breech of any of the barriers of our first line of defense, the next line of our innate immune system steps in. 


THE SECOND LINE OF DEFENSE

If a pathogen breeches the epithelial lining, the immune system will mark, or “flag”, the pathogen as “non-self.”  Antigens will bind tightly to this pathogenic invader which will inhibit its growth, replication, or interaction with human cells.  This mechanism is called neutralization. 

Mast cells, neutrophils, macrophages, antibodies and immunoglobulins can all work together to render the pathogen inactive and trigger an inflammatory response (redness, swelling, heat, pain).  The presence of an antigen triggers the activation of complement. When complement is activated it attaches to the pathogen and acts as a flag for effector cells. Effector cells then bind to the antigen-complement complex, and engulfs and destroys the pathogen.

THE THIRD LINE OF DEFENSE

The third line of defense involves the adaptive immunity; an immune response that adapts and changes to what we’re exposed to in our environment. The third line of defense recruits mature lymphocytes and various other cells) to increase the power of the immune system.  

During lymphocyte maturation, each cell is programed to make a single species of cell surface antigen receptors. The population of circulating lymphocytes targets millions of receptor species, which enables all possible pathogens to be recognized. During an infection only those lymphocytes bearing receptors that recognize the specific pathogen are selected to participate in the response.  The immune system asks that their numbers be expanded and matured to produce more effector cells of the same type. The full benefit of the adaptive response occurs about a week after the infection began. After the infection is resolved, we are left with an abundance of lymphocytes and antibodies for that particular pathogen.   We hold memory of that infection so that if the same pathogen breeches the 1st and 2nd lines of defense again, the system remembers it and may destroy it before external symptoms arise. 

Our bodies also have to clean up the mess of the killed pathogen, the inflammation or histamine response, the battlefield if you will. This looks like sneezing, coughing, vomiting and diarrhea, etc. These are normal responses and should not be repressed. They should be closely monitored for signs of imbalance or emergency. 

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In order for natural immunity to formulate the appropriate defense and produce a memory of the infection, the pathogen needs to pass through all three defensive layers of immunity.  

If the pathogen is not flagged.  If it is not denoted as “non-self,” there creates confusion and the immune system starts attacking the pathogen as “self.”  Let me repeat and restate that...  If the pathogen skips the first and second line of defense and is not flagged as “non-self,” then it is classified as “self.”  If the pathogen is classified as self, and the immune system becomes aware of it, then the immune system starts attacking “SELF.”  When self/non-self recognition is lost and the body starts attacking itself, it is called autoimmunity.

There is so much more to this discussion: 

How to support the immune system.  
How to nourish the immune system.  
How to rebuild the immune system.  
What throws the immune system off.  
What does an infant and child immune system look like?  
How does the immune system transfer from mother to child?  
How does the immune system mature?

And then, 

What is the purpose of a vaccine?
How does it effect the immune system?
What happens when reactions occur?  

... The discussion can go on forever.  

Chew on this for now.  More later.