Immunology 101The human immune system is incredibly complex. In simplistic terms, it can be divided into two main branches: the innate and the cellular or adaptive immune systems. The innate immune system is akin to soldiers acting as sentries guarding the fortress, the first line of defense against foreign invaders. These sentries are constantly on guard at all portals of entry into the fortress of the body such as the nose, sinuses, mouth, throat, lungs, the whole length of the stomach and intestines, the eyes, and the entire surface of the skin.
This frontline defense starts its own fight against enemy invaders and also calls in a powerful second line of defense, the cellular or adaptive immune system. This second line of defense is analogous to a corps of engineers who receive instructions from the sentries for how to make specific weapons called antibodies that are custom-made to bind and neutralize each individual foreign invader encountered. It takes time, usually a few weeks, for the engineers to make effective antibodies for each new invader. Once the antibodies bind to and neutralize the foreign invaders, other immune cells called macrophages come along like "pac-men" to gobble up, digest, and destroy the dead enemies and debris from the battlefield.
Natural Immunity to SARS-CoV-2When SARS-CoV-2 viral agents enter the body through the nose or mouth, they land on the mucous membranes of the nose, sinuses, and throat. This is where all respiratory viruses typically land and try to establish a beachhead. Some SARS-CoV-2 viral particles manage to evade the frontline sentries and break into the cells lining the nose and throat. They do this by tricking our cells by binding to, unlocking, and sneaking through specific "doors" in the cell wall called angiotensin-converting enzyme-2 (ACE-2) receptors. These receptors are meant for the enzyme ACE-2, which does important work in many places throughout the body. So SARS-CoV-2 not only gets in through this door, it also blocks ACE-2 from doing its job.
Cells can be thought of as little factories, producing all kinds of things the body needs. Once inside cells, these viral agents hijack the cell’s machinery and use it to reproduce themselves to such an extent that the cells become completely filled with viruses to the point of bursting open, which releases more viruses, which will go on to infect more cells.
This process of invasion can last for up to five days before there are enough viruses made to make you feel ill or be contagious to others. Many researchers believe it's only after you develop symptoms of congestion, runny nose, fever, sore throat, or cough that there are enough viral particles in your body to be able to spread to others.
These killer T-cell lymphocytes are the most important branch of the body’s fighting arsenal against viruses. They are very efficient at killing cells that have been infected by viruses, and they remember how to recognize previously encountered enemies for many years.
Every foreign invader, be it a virus, bacteria, or fungi, has proteins on its surface, like a fingerprint, that make it identifiable to the body as a foreign invader. These proteins are called antigens. An antigen is any of these protein molecules that alert the immune system. The most famous antigen in the world is no doubt the spike protein found on SARS-CoV-2.
When one is infected by the SARS-CoV-2 virus, the B-cell engineers are instructed to make secretory IgA antibodies to bind to the spike protein and several other antigens of the virus’s outer coat or body. Each one of these IgA antibodies is made by a different regiment or clone of B-cells.
Antibodies incapacitate or neutralize viruses by binding to specific antigens of the virus for which they were designed, forming antigen-antibody complexes. It’s a little bit like throwing handcuffs and chains around a foreign enemy. These complexes are then gobbled up and digested by macrophages, the pac-men-like immune cells we mentioned earlier.
Once the B-cell engineers have learned how to make specific IgA antibody weapons against several different parts of the virus, they release their IgA antibodies onto the mucus lining the nose, sinuses, throat, and breathing tubes in the lungs. These secretory IgA antibodies are always on guard to immediately bind with any of the same or similar viral antigens, or parts of the enemy for which they were designed, that may come in at any time with the air we breathe.
Foreign invaders that come into the body by routes other than the nose, mouth, and throat result in the production of different kinds of antibodies called IgM, IgG, and circulating IgA antibodies. These antibodies are designed to protect the internal organs of the body from enemies that spread and attack via the bloodstream. Unlike secretory IgA, these other antibodies are unable to reach the lining of the nose, mouth, throat, or breathing tubes and can't in any way protect these parts of the body from attack by respiratory viruses.
It's important to note that naturally acquired T-cell and B-cell immunity can last for a long time in the body. The secretory IgA antibodies and the killer T-cells that have been primed by a particular virus will react quickly and efficiently against the same or similar enemy attack. This means that naturally acquired immunity from a SARS-CoV-2 infection offers protection against future variants of SAR-C0V-2 as well as other similar coronaviral infections.
Immunity From the COVID-19 Vaccine?The COVID-19 vaccines, injected into the muscle of the arm, contain instructions from either mRNA (Pfizer, Moderna) or DNA (Johnson & Johnson) wrapped up in nano-lipid particle balls that direct cells in the body to manufacture a synthetic spike protein similar to but slightly different from the spike protein found on the surface of the SARS-CoV-2 virus.
One of the key differences between natural immunity and vaccine-induced immunity is the number of antigens the immune system learns to recognize. During natural immunity, the immune system is dealing with the whole virus and learns to recognize different pieces of the virus's body, which scientists call antigens. After receiving the COVID-19 vaccine, the immune system only learns to make antibodies to the spike protein antigen.
The free-floating synthetic spike protein, which can be made anywhere in the body, will attach to those specific doors or ACE-2 receptors that exist not only in the nose, sinuses, mouth, and breathing tubes, but also in many different organs and tissues in the body, such as the heart, blood vessels, brain, liver, kidneys, blood vessels, spleen, stomach, intestines, lymph nodes, skin, thymus, bone marrow, and ovaries. Some scientists are concerned about the possibility that our immune systems might recognize cells making the synthetic spike protein as enemies, just like they do with any cells infected with the SARS-CoV-2 virus, resulting in autoimmune disease.