the world where microorganisms are everywhere - including trillions of
them in each of us - the body had to develop natural defense against
them. A complex network of specialized cells, glands, organs, specialized
proteins and molecular messengers - making up body's immune system -
viruses and parasites from
over-multiplying inside the body and inflicting harm to body processes.
In addition to protecting the body from foreign invaders,
this body defense system has the
capability of recognizing and destroying worn-out body cells, as well as
abnormal cells, which are always potentially harmful to the system.
In detection and elimination of
pathogens (disease-causing microorganisms), the immune system has to
make distinction between them and harmless or friendly microorganisms,
as well as body's own cells, protein-based compounds like
hormones and many other molecular types used by the body. This requires very complex system of
inter-cellular communication, which is only partly understood.
The center of immune system are
lymphatic system and
lymphoid tissues and organs -
and others. Lymphoid tissue in the bone marrow produces variety of
white blood cells (leucocytes), each with different set of properties
and actions. Through the continuous process of positive and negative
selection (elimination) taking place in the bone marrow, thymus and,
finally, anywhere within the body, body produces - or clones -
generations of successful immune cells capable to carry out the task of
detecting and destroying pathogens, while incurring minimum damage to
"self" - body's own cells and molecules.
These immune cells move through the bloodstream, lymph system and
tissues, always on a lookout for foreign bio-material endangering the body.
How monumental is this task can be
illustrated with the number of different proteins used by the immune system,
estimated at around 1 million, with up to 100 million variations in immune
cells' receptor types. At the same time, the number of different foreign
proteins and patterns to be recognized by these receptors could be as high
as 10,000 trillions!
First line of defense
The first line of body's
defense against pathogens
starts with its passive barriers:
physical obstruction to pathogens' advance and/or inhospitable for their
survival due to their acidity, alkalinity or temperature. These barriers are
passive because they do not detect pathogens, nor react to their presence.
However, once pathogen clears this first defense line, the
body needs to detect and destroy the intruder
as soon as possible. The time factor is critical: pathogens tend to multiply
exponentially, so if they are given twice the time they need to double in
numbers, there will be four times as many, and if they are given only
another half of that time, there will be eight times as many, and so on...
The larger number of pathogens, the greater damage they can do, and the
harder for the body to mount successful defense.
Second defense line: Innate immune system
Part of the
immune system in charge of delivering that first punch to pathogens that penetrated the first defense line is so called
innate immunity. It
forms body's second defense line. Immune cells and chemical communications
of the innate system are created from the inherent, parent's genetic code.
Their primary mode of action is through:
called complement response,
consisting of a cascade of reactions of some 25 immune proteins produced in the
spleen and liver, which detect and
finally destroy invaders either by rupturing their outer membrane, or having it coated with complement fractions, marking them to be eaten by immune cells called phagocytes
(in old Greek, phago is "eat", and cyto is "cell")
phagocytes, white blood cells
which either react to the complement mark, or detect pathogens with some other
receptor type, engulf it and digest with their enzymes (phagocytes include
- the latter being monocytes settled in speciffic tissues, like liver, spleen and
granulocytes, white blood
cells like eosinophils and basophils, which pack granules of toxic
chemicals, like histamine, that burst and spray onto perceived pathogens;
special form of basophils, called mast cells, are distributed primarily along blood
vessels and, together with other granulocytes, have as their main function
breaking down antibody-antigen complexes (that is, destroying antigens
marked by antibodies), part of which is initiating allergic responses
(neutrophils are both, phagocytes and granulocytes, since they use granules
of toxic chemicals to decompose pathogens they engulf)
cytokine action, where
cytokines are signaling protein molecules produced by immune system cells,
but also by damaged regular body cells (the latter being called chemokines); they trigger a
multitude of effects, among the major ones being inflammatory response
(characterized by locally increased blood flow and permeability, enabling
better access for the immune response), increase in body temperature, which
reduces pathogen activity while stimulating that of the immune system, and
signaling to the liver to produce acute phase proteins, a type of complement
marking bacteria to be eaten by macrophages (cytokines, like
are also secreted by the adaptive immune system cells; cytokine called
secreted by both macrophages and T-cells, stimulates T-cell production)
The final defense: adaptive immune system
All this may not be enough to stop pathogen invasion. In such case,
the body mobilizes its third line of defense, so called adaptive immune
Unlike innate immune cells, those adaptive do specialize for specific
selective mutation controlled by the immune system.
The price to pay for such specialized response is time - it can
take days, or even weeks for it to fully develop. However, after the pathogen is
eliminated, certain number of these specialized cells continues patrolling
the body, keeping the "memory" of it, ready to launch much faster massive
response if that particular - or similar - pathogen invades again.
White blood cells (leucocytes) mainly carrying out adaptive immune
system response are lymphocytes.
Similarly to innate immune cells, their action is based on chemical
reactions between immune cell receptor molecules and a peptide or molecular
fragment on the surface of pathogen, called epitope.
The receptor-epitope connection is based on lock-and-key principle of matching
three-dimensional molecular structures, also involving electrical
charge. The degree of receptor-epitope match determines strength of
affinity, which has to exceed threshold minimum in order for the
adaptive immune system cell to
(with "B" for these cells going through their selective multiplication
process in the bone marrow),
specialized in pathogen detection and secretion of pathogen-specific
antibodies, which mark the pathogen (also antigen, or "non-self") for elimination by attaching to it to
form antibody-antigen complex, and
T-cells (with the "T"
label from their selective
production taking place in the thymus), which come in several forms - helper Th-cells, suppressor Ts-cell, cytotoxic, or "killer" Tk-cell
(also called natural killer cells),
which detect and destroy internally infected and abnormal (including cancerous) cells;
T-cells are much less versatile as pathogen detectors than B-cells, but have
key role in ensuring their proper function, as well as in initiating inflammatory
response (by activating macrophages), balancing the immune reaction by
suppressing leukocyte activity, destroying body cells infected by
intra-cellular pathogens (such as viruses, or malaria parasite), as well as
abnormal body cells, and so on.
lymphocyte forms represent the back bone of the adaptive
The inner workings of the immune function can be illustrated
by the process of creation and mutual dependence of B- and T-cells. B-cells
are created in the bone marrow, where they are selectively cloned to
tolerate "self" (body entity in all its constituent parts). After that, they
move to lymph nodes, where they are introduced to pathogens. Those that
succeed in binding
to pathogens leave lymph nodes and become plasma, or memory B-cells,
specialized to detect particular type of a pathogen and mark it with
B-cells that don't bind to pathogens are programmed to die.
The imperative of producing astronomically high number of
B-cell varieties, capable of detecting trillions of different
pathogens, dictates astoundingly high rate of their cellular
division/mutation inside lymph nodes. This, on the other hand, compromises
their "self" tolerance. In order to protect the body from possible harm
inflicted by autoreactive (attacking "self") B-cells, the immune system uses helper T-cells
to verify - using molecules of the Major Histocompatibility Complex (MHC) -
that what was detected by B-cell is not "self". If that is the case,
B-cell receives signal from T-helper cell, which activates B-cell's
production of antibodies. In the absence of this signal, B-cell dies.
For their part, Tk-cells which are cloned to self-tolerance
in the thymus, are controlled by a
signal given from innate immune system cells, that has to follow Tk-cell's
detection of infected, or abnormal cell. In the presence of tissue damage,
such signal could be given by damaged cells even to autoreactive Tk-cells,
enabling them to survive and multiply. This could be one of the
mechanisms of developing auto-immune disorders.
importance of the adaptive part of the immune system is in providing needed
volume and flexibility in pathogen detection and elimination. Those that can
be detected and destroyed by
the innate immune system are many
millions, but still only a fraction of all existing pathogens. Also, there
is no clear dividing line between the two immune system "departments": they vitally assist
each other, to the extent that neither could possibly remain functional and
effective without the other.
Immune system antagonists
Among the factors that
inhibit activity of the immune system are negative outlook, acute and
chronic stress, smoking, alcohol, overweight, insufficient rest (sleep) time, high
sugar intake, high blood lipids, and nutritional deficiencies7.
In his book "Your Body Doesn't Lie", Dr. John Diamond
describes how even simple negative thoughts - about tragic events, bad
experiences or expectations, hateful feelings, fear - can directly affect
thymus gland, lower your life energy and suppress all body functions,
including the immune system. According to his experiments,
thymus is the
first organ to be affected -
positively or negatively - not only
by stress and emotional states, but also by food, posture, or physical and
Obviously, this implies a great number of factors possibly
negatively affecting your immune system. Many of them may be relatively
insignificant alone, but the combined effect of a multitude of
such factors can have significant impact. And most of us are widely exposed
to these immuno-suppressing factors: from our own
negative emotions, to
negative people and events around us, stressful daily routines, that also
often drive us to unhealthy lifestyle (smoking, alcohol, insomnia, sedatives,
painkillers, lack of rest, lack of exercise, fast foods, overeating and
other addictions), synthetic materials,
foreign chemicals, fluorescent
light, noise, food additives, denatured, over-processed foods,
electromagnetic field, loud, aggressive music, and so on...
Immune system support
Positive attitude, healthy lifestyle and healthful diet -
with accent on green leafy vegetables - are all critically important for
proper, efficient functioning of the immune system.
Particularly beneficial nutrients include vitamins
function with thymus extract strengthens the immune system,
particularly antiviral and cancer-protective responses (Tk-cells). According
to Dr. Diamond, there are simple natural ways of directly stimulating thymus
function. One is
by making sure that the tip of your tongue is resting against the roof of your mouth,
centered about 1/4 inch behind your teeth. The other is by lightly tapping
against the top of your breast bone with a finger,
several times; this has been shown in experiments to have an immediate
stimulating effect on the thymus (which is located beneath the breastbone,
at the 2nd rib height).
Enhancing spleen function
by taking spleen extract also stimulates immune system, especially
resistance to bacterial infections.
Among the herbs
stimulating immune system - particularly the lymphatic system - are
Echinacea, Cleavers, Golden Seal and Astragalus.