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    Of Antibodies, Antibiotics, and Antigens: A Simple Guide, Can’t Know the Program without the Players

    By Dr. Arthur Lavin

    We use so much jargon in medicine, it’s sometimes forgotten that not everyone knows all the secret handshakes.

    So in this article, we present a few terms that get used quite a bit, in the hopes that we can help many understand better what we are talking about when we talk about some of the actions of our immune system.

    First, the Immune System

    The study of the human body can be organized according a handful of parts of the body that work together towards a specific goal.

    For example, all the organs of the gut, the liver, the mouth, can be grouped together into a set of structures that together take care of eating, and turning the food we eat into us.  We call that the digestive system.

    The circulatory system is made up of all the parts of the body that make sure blood flows where it needs to, supplying the whole body with food, oxygen, and waste clearance, and includes all our arteries, veins, capillaries, and of course, the heart.

    There aren’t that many grand systems, but one that gets a lot of attention is the one charged with making sure no life form attacks and hurts us, and it’s called the immune system.

    Most systems have an organ that defines the whole project.  For the circulatory system it’s the heart, for the digestive system the gut, for the nervous system it’s the brain.

    Not so for the immune system.  There is no one organ that runs the immune system.

    The immune system is really a spy network, with billions upon billions of its cells placed in every square millimeter of the human body, on alert, looking to see if this cell or that bacteria, or that virus it encounters could cause harm.

    Here is a picture of a white blood cell destroying an anthrax germ:

    The white blood cell in this photo is yellow, and the orange rods are the anthrax germ.

    I love this photo because it captures the very essence of this system.

    At any point in time, these billions upon billions of immune system cells must decide, is this cell or virus next to them friend or foe?

    If friend, it must remain dormant, just sit there and do nothing.  Otherwise, it may end up destroying our own selves.

    If foe, it must go into action and destroy the enemy.

    This photo shows a white blood cell having made the decision to go on the attack, and activate its ability to engulf the enemy cell (see the lower end of the anthrax rod sticking out of the white blood cell that just gulped that part of the bacteria?  It’s the yellow finger of the cell sticking out at the lower left corner of the photo.

    This task, of deciding whether every cell next to is either friend or foe is staggeringly tough to pull off.  How does the lonely immune system cell know if the cell next to it needs to be obliterated or left alone, what makes it dormant, what makes it go wild?

    It turns out their is a tremendous hierarchy of different immune system cells, let’s take a brief tour.

    The Immune System Cells

    T-cells

    Sitting a top the kingdom of the immune system is the T-cell.  It’s called that because it’s made in one of the few organs of the immune system, the thymus, a small organ just behind our sternums in our chest.  It’s at its largest at birth, by puberty it’s nearly gone!

    The T-cells come in various forms, but together they really are the brains of the operation.  If you have ever had mono, you are very likely to never get it again, but only because there is a group of T-cells in your body that have memorized the nature of the virus that causes mono.  And that group stays alive in your body the rest of your life, ready to say, should a mono virus come your way again, I recognize you, and then directing an orchestra of billions of other immune system cells to go after the virus and all cells containing it in your body.

    The upshot?  You don’t get sick from mono again.

    B-cells

    These cells are the only cells in the body that make antibodies, more on that below.

    They are called B-cells because they were discovered in a small set of organs in chickens called bursa, where they are formed in chickens.

    The closest thing we have to chicken bursa are lymph nodes, where most of our B-cells are in residence, waiting around to be told by the right T-cell to get going and make it’s antibody.

    White Blood Cells (WBC’s)

    This group of cells is easy to understand how it got its name.  There are three types of cells in our blood, red blood cells that carry oxygen, platelets that clot, and everything else is a WBC.

    Many of these WBC’s are actually T and B cells.  But others are the very curious macrophages and neutrophils.  These are the soldiers of the system.  If the T-cell says attack, its the macrophages and neutrophils that are thrown into battle.

    Macrophages

    Parked in every tissue of the body, macrophages are the sentries of the immune system.  They taste every protein on the surface of cells and present what they find to the T-cell they report to.

    To do that, these gorgeous cells drape themselves about the suspect cell, and get a very precise read of all its surface proteins.

    Take a look:

    The wispy, flowery white poem is the macrophage.  The red dot is a cancer cell.  The macrophage is just starting to fold its drapes about the cell, starting to read its surface, and then will report.

    Now, let’s pause for a moment to admire the sheer grace and beauty of this cell.  We each have billions and billions in us doing this act every moment.  Astounding!

    Antibodies

    Everyone talks about antibodies, but I think it helps to know a few basics about the immune system to get know what an antibody is.

    First, the word, it’s ridiculous.  Anti means against, and body, well, means body.  An antibody is not something against all bodies.

    An antibody turns out the be a molecule, which in turn, is a group of atoms that are joined together.

    All antibodies arrange their atoms to create a Y-shaped molecule.

    The stem tells us what type of antibody it is, more on that soon.  The type of antibody defines what the antibody will make happen should the Y-part get activated.  For a certain class of antibody, the stem is the same for every antibody molecule.

    The Y part is incredible.  It varies to a dizzying extent. There are trillions upon trillions of variations of the Y-part.  And for each example of a particular Y part, that part can attach to one and only one protein.   Any such protein an antibody can attach to is called an antigen, more on that later too.

    But, don’t you think it’s time for another picture?  This time it is an art piece, antibodies don’t actually look like this, but the schema helps understand what I just said about them:

    In this drawing it’s pretty easy to see that I was not kidding that antibodies have a Y-shape to them.

    Notice the stem, one is blue, one is yellow.  If these two were part of the same class of antibodies, the stems would be exactly identical to each other.

    Aw, but the wonder of the Y-part.  See where on the left there is a purple, small, jigsaw puzzle looking thing in the shape of a very squat T?  That’s the artists rendition of the one and only protein that fits into the blue antibody.

    On the right, the protein is deep red, and has a completely different shape, and see, the end of each Y of the antibody fits that red protein exactly.

    It’s the fact the tip of each Y of an antibody has a very, very, very precise shape that means only one protein could possibly fit into that spot that makes the antibody able to respond to only one protein.

    That’s why we are always talking about antibodies for this or that.  Do you have an antibody to measles in your blood, or has your body made an antibody to tetanus?

    Antibodies typically will attach to proteins that only are related to harm, proteins only seen on particular germs, or cancer cells.

    The system works because every germ has some unique proteins.  If an antibody exists to attach to one of these unique proteins, then the immune system can recognize the threat, turn on its soldiers and destroy the germ or cancer cell.

    Classes of Antibodies

    In each of us humans, there are 5 classes of antibodies.  Each class has its own stem and that stem defines what the antibody does when the Y-part attaches to its one and only one protein.

    Scientists don’t like using the word antibodies, too easy, we call them immunoglobulins, or proteins for the immune system, since the Y-shaped molecule is itself a protein.  The short version of the word immunoglobulin, is Ig

    Here are the classes:

    • G
    • A
    • M
    • E
    • D

     

    G

    The G class is the one most of us talk about.  G class antibodies, or immunoglobulins G, or IgG, are the type of antibodies that respond to known germs.  They are only made during or after an infection, not around for the first round of the infection.

    So, it’s the G class that makes us immune, or not susceptible, after one round of the illness.

    For example, if you get measles, typically you can never get that infection again, and since there is only one measles germ, you can never get measles ever again.  That’s because for the rest of your life your body is making a G class of antibody, an IgG that is dedicated 100% to the protein on the measles virus.

    M

    The M class is the type that comes to the rescue in the middle of the fight, with bacteria and viruses. When you get a cold, it’s the M-class, or IgM that we make a ton of, attaching to the cold virus and directing the utter destruction of anything to do with that virus, it’s the only reason we actually recover from colds.

    Once you get well, the M-class, or IgM go away, slowly.

    So, if you wonder if that last sore throat was mono, check the IgM for mono, if it’s negative you probably did not have an active infection.

    If the IgG or G-class antibody for mono is positive, and the IgM is negative, it means you don’t have it now, but did in the past.

    A

    The A class is a coating strategy. A class antibodies, or IgA’s coat any tissue that touches air, tissues that come into contact with viruses and bacteria that land on us in vast numbers every moment.

    IgA’s are found in our mouth, along the gut, the tears, the genital areas, the airway.

    Their job is to attack the germ on arrival and prevent an infection.

    E

    The E class is tasked with taking on worms.  Why bother with that?  Well until very recently and across most of the world today, nearly every human was loaded with worms.  Even now, about 10% of Americans are walking around with pinworms in their gut, completely unaware.

    The E class of antibody or IgE, is built to recognize proteins on worms, and activates an all out attack on them by our immune system.

    And, yes, there is one other task the E class takes on, sadly.

    It’s allergies.

    Allergies are the result of a protein that has nothing to do with worms attaching to an E class antibody, or IgE.  You see, the stem of the IgE is the only antibody stem that is planted in a mast cell, another member of the immune system.  Mast cells are loaded with items like histamine, and they pop all those items out when the right protein attaches to the right IgE.   This is what kills worms.

    But, unfortunately, we have developed a whole range of IgE’s that attach to harmless proteins like those found in pollen, dust, mold, cats, dogs, and peanuts.

    If you have an IgE that attaches to pollen, mold, animal, or food, and it’s armed on a mast cell, and you come across that protein, the immune system opens fire, also known in this instance, as an allergic reaction.

    D
    nothing.

    I don’t say this often, but we don’t know much about the D class of antibody or IgD.

    Some functions are known, but not many, one of the great puzzles in medical science.

    Antigens

    There is a nearly infinite variety of proteins in life.

    This is no coincidence.

    Proteins are the key method life uses to create signals, to our own life our own bodies, to other life.

    That’s because a protein is a chain of thousands of amino acids (there are about two dozen types of amino acids in humans), and each chain folds in its own distinct way, creating nearly infinite varieties of sculptures.  Each sculpture is, therefore, a unique signal of information.

    This information helps direct every single chemical reaction in the body, including the formation of DNA, every function of a cell, every thought we have, in short life.

    If any protein fits into an antibody, that protein is called an antigen.

    It’s an odd word, again anti means against, but gen is a very old sound, meaning that which is produced.

    Antigen doesn’t really mean against that which is produced, but the word is with us.

    If you ever hear the word antigen, know that it refers to a very specific protein that some antibody will attach to, recognize.

    Antibiotics

    This third and final word in this primer on three anti- words, is the simplest to describe.

    An antibiotic is any medicine that kills bacteria, that’s it.

    The word means against life.  But again, not a good root meaning for its reality, antibiotic is not against life, it kills bacteria, not all life.

    BOTTOM LINES

    1. The immune system is the system in the body charged with finding threats to life such as germs and cancer, and destroying them.
    2. The immune system is brilliant, vast, only matched in depth and range of responses by the brain.  It includes master mind cells, the T-cells, that direct the huge armies of immune cells in the body, telling each whether to remain dormant, or go on the attack.
    3. Antibodies are Y-shaped molecules whose stem defines each as part of either the G,A,M,E, or D class of antibodies.  The Y part is fashioned to be able to attach to one and only one protein.  Once attached the antibody activates a sequence of events depending on whether it is a G, A, M, or E class antibody (D remains a question).  Antibodies recognize proteins.
    4. Antigens are the proteins antibodies recognize.
    5. Antibodies are not part of the immune system, they are medicines that kill bacteria.

    The medical world uses these three anti-words all the time, so we thought it would be helpful to share what they mean.

    To your health,
    Dr. Arthur Lavin

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