How Vaccines Work and How You can Support the Work they are Doing by Boosting your Immune System: Part 1

The basic function of the immune system is to “screen” the body for what is “self” and what is “non-self”. It does this by “looking” for antigens—small molecules (or parts of bigger molecules) that either are part of your body (self) or don’t belong in your body (non-self). This “screening process” or surveillance is responsible for monitoring for bacteria, viruses, fungi, and parasites of all sorts. It is also thought to kill off cancer cells that may arise, for blood transfusion reactions, for allergic reactions, for graft-vs-host disease in transplantation, and for “walling off”, and helping to remove harmful environmental substances.(2)

The immune system is complex—it HAS to be in order to do all that it has evolved to do and to provide you with protection against all sorts of pathogens, including viruses, bacteria, fungi, and parasites. The immune system first has to figure out the differences between you and these pathogens—that occurs when the immune system recognizes something different about the pathogen—an antigen often on the surface of the pathogen. An antigen can be defined as any substance that can produce an immune response.

The immune system has ways of dealing with all of these, but it has to learn about them first. There are two essential ways the immune system can learn to discriminate between self-antigens and non-self-antigens. The first is via “natural immunity”, which occurs when an organism encounters a non-self-antigen carried by some pathogen.

The second way that the immune system learns is by vaccination. Vaccination is a way of teaching the immune system to respond to a specific pathogen—most recently, the coronavirus—in order to remove it from your system, so it doesn’t damage your lungs, nervous system, heart, or any other organ or system.

The Organization of the Immune System

There are two types of immune systems:

• “Natural” or innate immunity
  • We are born with this type of immunity. Innate immunity consists of physical barriers (intact skin and tight junctions between skin cells or the cells lining of the digestive tract); mucous membranes in the mouth, nose, vagina; cells which (literally) eat invading pathogens; proteins in the blood to block the movement of invading germs…and to make them “tastier”; receptors that sense an invading germ and send off signals to other parts of the immune system; and—importantly—the inflammatory response which can directly kill off invading organisms.
  • Innate immunity is non-specific but relatively rapid. It has no “memory”. On secondary infection, it essentially behaves in the same way it did the first time around.
  • Innate immunity uses both cells (e.g., Basophils, phagocytes, Natural Killer (NK) cells, dendritic cells) and cytokines. These cytokines (cellular chemical messengers) communicate between cells of the immune system and include Tumor Necrosis Factor (TNF), interleukins, interferons, and other chemokines.
• Acquired or adaptive immunity
  • This form of immunity likely evolved for one reason—innate immunity is often not enough to prevent serious disease. Why? Probably because it is not specific enough…it is a bit like using a hammer to open a door—the door is open, but it is no longer useful as a door. On the other hand, using a key to unlock a door leaves the door’s function intact. Another analogy that is often used is the difference between doing surgery with a scalpel (accurate and precise) versus using a kitchen knife—not so accurate and not so precise!
  • Acquired immunity is specific and “remembers” so that when an organism is faced with the same pathogen, the acquired immune system rapidly and specifically responds. While the initial acquired immune response is relatively slow, when faced again with the same or similar antigen, the response is rapid. Acquired immunity is, in general, much more efficient than natural or innate immunity.

There are also two basic “arms” of the immune system.

• Cellular immunity
  • Cellular immunity involves cell-to-pathogen contact, and the release of cellular messengers called cytokines.
  • There are quite a few cell types involved in cellular immunity. Different cells – mainly specialized T cells—work with cytokines to kill, maim, damage, and otherwise remove infectious organisms.
• Humoral immunity
  • Humoral means antibody-based. In humoral immunity, specialized cells, the B cells, produce “Y” shaped antibodies that either act alone or in “clumps” of 2-5 “Y’s” to glom onto (bind) antigens on the pathogen. This immobilizes and neutralizes the invading organism and prepares them to be eaten (by phagocytes), killed, and removed from the body.
    • The three most important antibodies are IgGs, IgMs, and sIgA. (Ig= immunoglobulin=antibody). The “s” before the IgA indicates it is secreted—this is often the first antibody to appear in mucous tissue like the nose or mouth and is VERY important in stopping respiratory viruses. IgM is usually the first type of antibody produced during an infection in the blood, while IgG is usually produced as a learned response (based on immune memory) with a second infection or after a vaccination with a booster shot.

The immune system learns by doing—so the first time an infection occurs, the ancient, basic part of the immune system—the innate immune system—sends off cells, some non-specific binding proteins and produces various cytokines that just kill, maim and damage everything that seems different and foreign (non-self). The innate immune system provides much more of a machete-based approach—broad and non-specific, cutting down everything in sight that may be non-self. While this is happening, another basic part of the immune system is learning about that pathogen—this is the acquired immune response and will start to make very specific antibodies and often provide a very specific cellular immune response. This is the more specific—a chef’s knife or scalpel approach.