Immune System:

Introduction

Inside your body there is an amazing protection mechanism called the immune system. It is designed to defend you against millions of bacteria, microbes, viruses, toxins and parasites that would love to invade your body. To understand the power of the immune system, all that you have to do is look at what happens to anything once it dies. That sounds gross, but it does show you something very important about your immune system.

When something dies, its immune system (along with everything else) shuts down. In a matter of hours, the body is invaded by all sorts of bacteria, microbes, parasites... None of these things are able to get in when your immune system is working, but the moment your immune system stops the door is wide open. Once you die it only takes a few weeks for these organisms to completely dismantle your body and carry it away, until all that's left is a skeleton. Obviously your immune system is doing something amazing to keep all of that dismantling from happening when you are alive.

An antigen is any substance that elicits an immune response, from a virus to a sliver.

Fluid Systems Of The Body

There are two main fluid systems in the body: blood and lymph. The blood and lymph systems are intertwined throughout the body and they are responsible for transporting the agents of the immune system.

The Blood System

The 5 liters of blood of a 154 lb person constitute about 7% of the body's total weight. The blood flows from the heart into arteries, then to capillaries, and returns to the heart through veins.

Blood is composed of 52% to 62% liquid plasma and 38% to 48% cells. The plasma is about 91.5% water and acts as a solvent for transporting other materials. Blood is slightly alkaline about pH 7.40 and a tad heavier than water.

All blood cells are manufactured by stem cells, which live mainly in the bone marrow, via a process called hematopoiesis. The stem cells produce hemocytoblasts that differentiate into the precursors for all the different types of blood cells. Hemocytoblasts mature into three types of blood cells: erythrocytes (red blood cells or RBCs), leukocytes (white blood cells or WBC's), and thrombocytes (platelets).

The leukocytes are further subdivided into granulocytes (containing large granules in the cytoplasm) and agranulocytes (without granules). The granulocytes consist of neutrophils (55% to 70%), eosinophils (1% to 3%), and basophils (0.5% to 1.0%). The agranulocytes are lymphocytes (consisting of B cells and T cells) and monocytes. Lymphocytes circulate in the blood and lymph systems, and make their home in the lymphoid organs.

There are 5000 to 10,000 WBCs per cubic mm and they live 5 to 9 days. About 2,400,000 RBCs are produced each second and each lives for about 120 days (They migrate to the spleen to die. Once there, that organ scavenges usable proteins from their carcasses). A healthy male has about 5 million RBCs per cubic mm, whereas females have a bit fewer than 5 million.

The goo on RBC's is responsible for the usual ABO blood grouping, among other things. The grouping is characterized by the presence or absence of A and/or B antigens on the surface of the RBCs.

The Lymph System

Lymph is an alkaline pH greater than 7.0 fluid that is usually clear, transparent, and colorless. It flows in the lymphatic vessels and bathes tissues and organs in its protective covering. There are no RBCs in lymph and it has a lower protein content than blood. Like blood, it is slightly heavier than water.

The lymph flows from the interstitial fluid through lymphatic vessels up to either the thoracic duct or right lymph duct, which terminate in the subclavian veins, where lymph is mixed into the blood. (The right lymph duct drains the right sides of the thorax, neck, and head, whereas the thoracic duct drains the rest of the body.) Lymph carries lipids and lipid-soluble vitamins absorbed from the gastrointestinal (GI) tract. Since there is no active pump in the lymph system, there is no back-pressure produced. The lymphatic vessels, like veins, have one-way valves that prevent backflow. Additionally, along these vessels there are small bean-shaped lymph nodes that serve as filters of the lymphatic fluid. It is in the lymph nodes where antigen is usually presented to the immune system.

The Human Lymphoid System Has The Following:

Innate Immunity

The innate immunity system is what we are born with and it is nonspecific; all antigens are attacked pretty much equally. It is genetically based and we pass it on to our offspring.

Surface Barriers Or Mucosal Immunity

Normal flora are the microbes, mostly bacteria, that live in and on the body with, usually, no harmful effects to us. We have about 1013 cells in our bodies and 1014 bacteria, most of which live in the large intestine. There are 103 to 104 microbes per cm2 on the skin (Staphylococcus aureus, Staph. epidermidis, diphtheroids, streptococci, Candida, etc.). Various bacteria live in the nose and mouth. Lactobacilli live in the stomach and small intestine. The upper intestine has about 104 bacteria per gram; the large bowel has 1011 per gram, of which 95 to 99% are anaerobes (An anaerobe is a microorganism that can live without oxygen, while an aerobe requires oxygen.) or bacteroides. The urogenitary tract is lightly colonized by various bacteria and diphtheroids. After puberty, the vagina is colonized by Lactobacillus aerophilus that ferment glycogen to maintain an acid pH.

Normal flora fill almost all of the available ecological niches in the body and produce bacteriocidins, defensins, cationic proteins, and lactoferrin all of which work to destroy other bacteria that compete for their niche in the body.

The resident bacteria can become problematic when they invade spaces in which they were not meant to be. As examples: (a) staphylococcus living on the skin can gain entry to the body through small cuts/nicks. (b) Some antibiotics, in particular clindamycin, kill some of the bacteria in our intestinal tract. This causes an overgrowth of Clostridium difficile, which results in pseudomembranous colitis, a rather painful condition wherein the inner lining of the intestine cracks and bleeds. A phagocyte is a cell that attracts (by chemotaxis), adheres to, engulfs, and ingests foreign bodies. Promonocytes are made in the bone marrow, after which they are released into the blood and called circulating monocytes, which eventually mature into macrophages (meaning "big eaters", see below).

Some macrophages are concentrated in the lungs, liver (Kupffer cells), lining of the lymph nodes and spleen, brain microglia, kidney mesoangial cells, synovial A cells, and osteoclasts. They are long-lived, depend on mitochondria for energy, and are best at attacking dead cells and pathogens capable of living within cells. Once a macrophage phagocytizes a cell, it places some of its proteins, called epitopes, on its surface, much like a fighter plane displaying its hits. These surface markers serve as an alarm to other immune cells that then infer the form of the invader. All cells that do this are called antigen presenting cells (APCs). The non-fixed or wandering macrophages roam the blood vessels and can even leave them to go to an infection site where they destroy dead tissue and pathogens. Emigration by squeezing through the capillary walls to the tissue is called diapedesis or extravasation. The presence of histamines at the infection site attract the cells to their source. Natural killer cells move in the blood and lymph to lyse (cause to burst) cancer cells and virus infected body cells. They are large granular lymphocytes that attach to the glycoproteins on the surfaces of infected cells and kill them. Polymorphonuclear neutrophils, also called polys for short, are phagocytes that have no mitochondria and get their energy from stored glycogen. They are nondividing, short-lived (half-life of 6 to 8 hours, 1 to 4 day lifespan), and have a segmented nucleus. [The picture below shows the neutrophil phagocytizing bacteria, in yellow.] They constitute 50% 75% of all leukocytes. The neutrophils provide the major defense against pyogenic (pus-forming) bacteria and are the first on the scene to fight infection. They are followed by the wandering macrophage's about three to four hours later.

The complement system is a major triggered enzyme plasma system. It coats microbes with molecules that make them more susceptible to engulfment by phagocytes.

Vascular permeability mediators increase the permeability of the capillaries to allow more plasma and complement fluid to flow to the site of infection. They also encourage polys to adhere to the walls of capillaries (margination) from which they can squeeze through in a matter of minutes to arrive at a damaged area. Once phagocytes do their job, they die and their "corpses," pockets of damaged tissue, and fluid form pus.

Eosinophils are attracted to cells coated with complement C3B, where they release major basic protein (MBP), cationic protein, perforins, and oxygen metabolite's, all of which work together to burn holes in cells and helminths (worms). About 13% of the WBCs are eosinophils. Their lifespan is about 8 to 12 days.

Neutrophils, eosinophils, and macrophages are all phagocytes.

Dendritic cells are covered with a maze of membranous processes that look like nerve cell dendrites. Most of them are highly efficient antigen presenting cells. There are four basic types:

Our major concern will be Langerhans cells, which are found in the epidermis and mucous membranes, especially in the anal, vaginal, and oral cavities. These cells make a point of attracting antigen and efficiently presenting it to T helper cells for their activation. [This accounts, in part, for the transmission of HIV via sexual contact.] Each of the cells in the innate immune system bind to antigen using pattern-recognition receptors. These receptors are encoded in the germ line of each person. This immunity is passed from generation to generation. Over the course of human development these receptors for pathogen-associated molecular patterns have evolved via natural selection to be specific to certain characteristics of broad classes of infectious organisms. There are several hundred of these receptors and they recognize patterns of bacterial lipopolysaccharide, peptidoglycan, bacterial DNA, dsRNA, and other substances. Clearly, they are set to target both Gram-negative and Gram-positive bacteria.

Adaptive Or Acquired Immunity

Lymphocytes come in two major types: B cells and T cells. The peripheral blood contains 20% to 50% of circulating lymphocytes; the rest move in the lymph system. Roughly 80% of them are T cells, 15% B cells and remainder are null or undifferentiated cells. Lymphocytes constitute 20% to 40% of the body's WBCs. Their total mass is about the same as that of the brain or liver. (Heavy stuff!) B cells are produced in the stem cells of the bone marrow; they produce antibody and oversee humoral immunity. T cells are nonantibody-producing lymphocytes which are also produced in the bone marrow but sensitized in the thymus and constitute the basis of cell-mediated immunity. The production of these cells is diagrammed below. Parts of the immune system are changeable and can adapt to better attack the invading antigen. There are two fundamental adaptive mechanisms: cell-mediated immunity and humoral immunity.

Cell Mediated Immunity

Macrophage's engulf antigens, process them internally, then display parts of them on their surface together with some of their own proteins. This sensitizes the T cells to recognize these antigens. All cells are coated with various substances. CD stands for cluster of differentiation and there are more than one hundred and sixty clusters, each of which is a different chemical molecule that coats the surface. CD8+ is read "CD8 positive." Every T and B cell has about 105 = 100,000 molecules on its surface. B cells are coated with CD21, CD35, CD40, and CD45 in addition to other non-CD molecules. T cells have CD2, CD3, CD4, CD28, CD45R, and other non-CD molecules on their surfaces. The large number of molecules on the surfaces of lymphocytes allows huge variability in the forms of the receptors. They are produced with random configurations on their surfaces. There are some 1018 different structurally different receptors. Essentially, an antigen may find a near-perfect fit with a very small number of lymphocytes, perhaps as few as one. T cells are primed in the thymus, where they undergo two selection processes. The first positive selection process weeds out only those T cells with the correct set of receptors that can recognize the MHC molecules responsible for self-recognition. Then a negative selection process begins whereby T cells that can recognize MHC molecules complexed with foreign peptides are allowed to pass out of the thymus.

Cytotoxic or killer T cells (CD8+) do their work by releasing lymphotoxins, which cause cell lysis. Helper T cells (CD4+) serve as managers, directing the immune response. They secrete chemicals called lymphokines that stimulate cytotoxic T cells and B cells to grow and divide, attract neutrophils, and enhance the ability of macrophages to engulf and destroy microbes. Suppressor T cells inhibit the production of cytotoxic T cells once they are unneeded, lest they cause more damage than necessary. Memory T cells are programmed to recognize and respond to a pathogen once it has invaded and been repelled.

Humoral Immunity

An immunocompetent but as yet immature B-lymphocyte is stimulated to maturity when an antigen binds to its surface receptors and there is a T helper cell nearby (to release a cytokine). This sensitizes or primes the B cell and it undergoes clonal selection, which means it reproduces asexually by mitosis. Most of the family of clones become plasma cells. These cells, after an initial lag, produce highly specific antibodies at a rate of as many as 2000 molecules per second for four to five days. The other B cells become long-lived memory cells. Antibodies, also called immunoglobulins or Igs [with molecular weights of 150 to 900 Md], constitute the gamma globulin part of the blood proteins. They are soluble proteins secreted by the plasma offspring (clones) of primed B cells. The antibodies inactivate antigens by, (a) complement fixation (proteins attach to antigen surface and cause holes to form, i.e., cell lysis), (b) neutralization (binding to specific sites to prevent attachment, this is the same as taking their parking space), (c) agglutination (clumping), (d) precipitation (forcing insolubility and settling out of solution), and other more arcane methods. Constituents of gamma globulin are: IgG-76%, IgA-15%, IgM-8%, IgD-1%, and IgE-0.002% (responsible for autoimmune responses, such as allergies and diseases like arthritis, multiple sclerosis, and systemic lupus erythematosus). IgG is the only antibody that can cross the placental barrier to the fetus and it is responsible for the 3 to 6 month immune protection of newborns that is conferred by the mother. IgM is the dominant antibody produced in primary immune responses, while IgG dominates in secondary immune responses. IgM is physically much larger than the other immunoglobulins.

Notice the many degrees of flexibility of the antibody molecule. This freedom of movement allows it to more easily conform to the nooks and crannies on an antigen. The upper part or Fab (antigen binding) portion of the antibody molecule (physically and not necessarily chemically) attaches to specific proteins [called epitopes] on the antigen. Thus antibody recognizes the epitope and not the entire antigen. The Fc region is crystallizable and is responsible for effector functions, i.e., the end to which immune cells can attach. Lest you think that these are the only forms of antibody produced, you should realize that the B cells can produce as many as 1014 conformationally different forms. The process by which T cells and B cells interact with antigens is summarized in the diagram below.

In the ABO blood typing system, when an A antigen is present (in a person of blood type A), the body produces an anti-B antibody, and similarly for a B antigen. The blood of someone of type AB, has both antigens, hence has neither antibody. Thus that person can be transfused with any type of blood, since there is no antibody to attack foreign blood antigens. A person of blood type O has neither antigen but both antibodies and cannot receive AB, A, or B type blood, but they can donate blood for use by anybody. If someone with blood type A received blood of type B, the body's anti-B antibodies would attack the new blood cells and death would be imminent. All of these of these mechanisms hinge on the attachment of antigen and cell receptors. Since there are many, many receptor shapes available, WBCs seek to optimize the degree of confluence between the two receptors. The number of these "best fit" receptors may be quite small, even as few as a single cell. This attests to the specificity of the interaction. Nevertheless, cells can bind to receptors whose fit is less than optimal when required. This is referred to as cross-reactivity. Cross-reactivity has its limits. There are many receptors to which virions cannot possibly bind. Very few viruses can bind to skin cells. The design of immunizing vaccines hinges on the specificity and cross-reactivity of these bonds. The more specific the bond, the more effective and long-lived the vaccine. The smallpox vaccine, which is made from the vaccinia virus that causes cowpox, is a very good match for the smallpox receptors. Hence, that vaccine is 100% effective and provides immunity for about 20 years. Vaccines for cholera have a relatively poor fit so they do not protect against all forms of the disease and protect for less than a year.

The goal of all vaccines is promote a primary immune reaction so that when the organism is again exposed to the antigen, a much stronger secondary immune response will be elicited. Any subsequent immune response to an antigen is called a secondary response.

Summary

Immunity can be either natural or artificial, innate or acquired=adaptive, and either active or passive.


10 Foods That Naturally Boost The Immune System

Foods that boost the body's immune system can offer a lot of healthy options for those who wish to be more conscious in what they take in. To be sustained, the immune system heavily depends on the stomach for support. Malnourished individuals are more susceptible to disease as opposed to those who observe a healthy nutritious diet. Below are some of these examples:

From a practical perspective, taking in food which boosts the immune system while enjoying it at the same time can be a cost effective way to maintain health. Coupled with a healthy lifestyle, sufficient rest and a positive outlook in life, staying healthy does not have to cost an arm and a leg.

Sources

http://www.immunesystemremedies.com/food-for-the-immune-system.html
http://www.sanitation-is-dignity.org/why_sanitation
http://immunedisorders.homestead.com/antibiotics.html
http://www.umm.edu/altmed/articles/echinacea-000239.htm
http://www.aafp.org/afp/2003/1015/p1539.html
http://www.naturalnews.com/027469_ginkgo_biloba_radiation_damage.html
http://altmedicine.about.com/od/herbsupplementguide/a/ganoderma.htm
http://www.naturalnews.com/027223_ASTRAGALUS_immune_system.html
http://www.naturalnews.com/032917_cats_claw_herb.html


By Jon Barron
Dated June 17, 2011

Strengthen Your Immune System And Fight Colds, Infections, Flu & Cancer

Your Immune System Plays Two Vital Roles In Your Body

In many ways, your immune system is the most awesome system in your body, easily rivaling your brain in terms of complexity, subtlety, and “self-awareness.”

Problems That Can Occur With The Immune System Are:

Of these problems, the first four are, in most cases, correctable. Only when the body is born without the ability to produce a key component are our options truly limited—but not necessarily hopeless.

OPTIMIZING YOUR IMMUNE SYSTEM IN FOUR EASY STEPS

Since the purpose of the body's immune system is to defend against attack and help initiate repair, the better it does it, the healthier we are. Surprisingly, not only are the natural immune boosters and pathogen destroyers safer than the drug approach (having far fewer side effects); they are also far more powerful than their pharmaceutical counterparts:

Other Issues

Downfalls of an Over-Reactive Immune System The bottom line is yes, you want your immune system to respond strongly to any pathogens -- but not too strongly. If it responds too strongly, the costs can outweigh the benefits. An overactive immune system can lead to sustained systemic inflammation, autoimmune disorders, overactive responses to allergens, even death, as in the case of avian flu. In this comprehensive report, learn what you can do to protect yourself, naturally and effectively.

Cancer and Your Immune SystemEvery single day of your life your body produces anywhere from a few hundred to as many as 10,000 cancerous cells as part of it's normal metabolic processes. That means no one, by definition, is ever cancer free, ever. The difference is whether that cancer takes root and grows, or is destroyed by your immune system. While the option of a mouse inspired miracle immune cell injection may be a future option for humans, it is not an option today. That leaves you only one option available right now: to optimize the immunity you already have.

Circulating Immune ComplexesAt a certain point, when the macrophage immune system is totally overwhelmed, the complementary immune system (AKA the complement system) kicks in. This secondary system is comprised of approximately 25 proteins/enzymes that activate in a cascading sequence and end with what's called the membrane attack complex. As its name implies, this complex attacks the cell walls of invaders. A secondary function of the complementary immune system is to help rid the body of CIC's (circulating immune complexes) as discussed in Chapter 5. If the overload on the complementary immune system is great enough, severe inflammation of tissue, caused by the activity of albumins, can result. The bottom line is that the body's tissue literally begins to attack itself. That is to say, we now have an autoimmune condition!


Immune System Information: Dr. Deb Baker - Page I

Immune System Information: Dr. Deb Baker - Page II

Immune System Information: Dr. Deb Baker - Page III

Immune System Information: Fasting

Immune System Information:Dr. William Campbell Douglass II 9/24/2002 - Your Best Defense

Immune System Information:Dr. William Campbell Douglass II 11/15/2002 - Sambucol

Immune System Information: Jon Barron 8/22/2011 - Anatomy And Physiology Of The Immune System, Part 1

Immune System Information: Jon Barron 9/5/2011 - Anatomy And Physiology Of The Immune System, Part 2

Immune System Information: Jon Barron 9/19/2011 - Anatomy And Physiology Of The Immune System, Part 3

Immune System Information: Jon Barron 10/2/2011 - Anatomy And Physiology Of The Immune System, Part 4

Immune System Information: Natural News 7/29/2010 - Vitamin D Is Essential For Activating Immune System Function


Immune System Information:Dr. Mercola 7/2/2000 - Kills Ebola Virus

Immune System Information:Dr. Mercola 7/30/2000 - Infections Peak on Shortest Days Of Year

Immune System Information: Dr. Mercola 12/24/2000 - Lipitor May Suppress Immune System

Immune System Information:Dr. Mercola 9/24/2005- Getting Dirty

Immune System Information:Dr. Mercola 2/18/2006 - Antidepressants

Immune System Information:Dr. Mercola 7/11/2007 - How To Supercharge Your Immune System

Immune System Information:Dr. Mercola 3/20/2008 - Immune Systems Increasingly On Attack


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