Immunity and the Immune System
When I spoke with Dr. Linda Strause, we discussed the Immune system, how it relates to immunity, and how we can optimize our immune response.
The take-home message from our was that maintaining overall health and wellness and a strong immune system is our best weapon in managing stress and anxiety. Linda Strause, PhD is the Vice President of Randy’s Club, a Professor of Nutrition at the University of California, San Diego, and has over 30 years of experience in drug development. This makes her extremely qualified to speak to this topic.
The immune system is complicated, very complicated. It is arguably one of the most complicated systems in the human body next to the brain. It is a ridiculously complex network of cells and signaling molecules that try to protect us from dangerous microbes, bacteria, and viruses, like the novel coronavirus. The various parts of the immune system, including dendritic cells, B-cells, T-cells, antibodies, and antigens, act on one another to amplify, excite, calm or transform one another with some parts actively smashing things to pieces. This interaction is a part of our normal physiological response, that back and forth to maintain homeostasis. However, sometimes this interaction can grow out of control. This is called a cytokine storm.
What the immune system is and what many may imagine it to be are very different things. There are 3 phases to the immune system which, if understood, helps to make this very complicated system a little easy to understand.
When the immune system responds to an infection by producing antibodies or mustering defensive cells, that’s called immunity. Immunity is a matter of degrees and perfect immunity, or absolute protection, never happens. When our bodies have specific antibodies to an infection, this reduces the risk of an acute infection which, in a population, means that there is less exposure. So immunity is something that happens both in the body of individuals and across populations. Polio was eradicated not by immunizing every single person but by immunizing enough people so that those who were not immunized were unlikely to be exposed to the virus. This so-called herd immunity means that a sufficiently high proportion of individuals are immune to the disease, primarily through vaccination, thus minimizing the spread of a contagious disease.
When cells become infected they stop behaving normally. This is one of the first signs of an infection and what triggers the release of proteins called cytokines. There are different types of cytokines. Some stimulate the production of white blood cells, which envelop and digest and destroy viruses. Others, called interferons, prevent viruses from replicating by interfering with cell metabolism. These reactions lead to inflammation. Symptoms of inflammation include redness, heat, swelling, and soreness. All these symptoms indicate that the immune system is working as it is intended to. This initial phase is quick and non-specific. During phase 1 the body’s goal is to shut down the infection long enough for phase 2 of our immune response to begin.
T-cells are highly specialized hunter-killers designed to kill one thing and one thing only, the invading particle. If a T-cell recognizes the virus particle then it quickly duplicates itself and sets off to join the battle. This takes several days which is why it makes up the second wave of our immune response.
Not all T-cells are killers, some are helpers that activate B-cells which create antibodies that prevent the virus from infecting new cells. So while the T-cells are taking out targets, antibodies are protecting the cells.
After the virus or other invading particle is cleared, most of our immune cells stand down, while some remain and remember, ever vigilant against a new infection. This is the third phase of activity and this is how our bodies can mount a rapid and effective response to an infection by a virus for which we have developed an immunity. Immunity means that we have T-cells trained to recognize, quickly destroy, and remove invading particles from the body.
What makes the novel coronavirus particularly dangerous is that it appears to delay the launch of phase 1, our innate immune system. This virus appears to inhibit the production of interferons which block the initial viral replication. This means that the initial period, instead of lasting 2–3 days, lasts 7–10 days. This brief window in which the virus can replicate without triggering the innate immune response also means that the adaptive response, phase 2 and 3, will also be delayed.
Most people will still be able to respond, adapt, and clear the virus after a few weeks, but some, unfortunately, don’t. There are several reasons why someone might not recover from COVID-19.
- Their initial infection may have been so great that it overwhelmed the body before the immune system could respond or adapt. These acute deaths often happen very quickly and often without notice. In one case a woman with a flushed face showed up to the hospital with blood oxygen levels so low she quickly went into respiratory distress and would have died if not for the immediate medical attention she received. She had no obvious symptoms and only went to the hospital out of an abundance of caution. In other instances, a person may have a weakened immune system resulting from old age or chronic disease. This may mean the innate response is less effective or slowed, allowing the virus to spread further before being confronted by the immune system.
- The inability of the immune system to clear the infection may result in a destructive immune response. The immune system releases chemicals in its effort to kill foreign invaders and may destroy healthy cells as well. Inflammation occurs and further stimulates the immune system. Even when people ultimately beat the virus, they continue to suffer organ damage caused by the virus and the immune response to the virus.
- Normally the immune system responds to different types of infections with different types of immune cells. Viruses, bacteria, parasites, and fungus all elicit a distinct response from our immune system. With COVID, the immune system seems confused and responds to all of the above. This doesn’t happen in all cases, only the most severe cases, but highlights how unusual this virus is and how unexpected it’s effects can be.
One of the most pressing mysteries about this virus is whether our adaptive immune response can provide lasting immunity. In other words, how long to the specialized t-cells adapted to this virus last. In July, a team of British researchers released a study showing that many COVID-19 patients lose substantial levels of their coronavirus-neutralizing antibodies after a few months. This is consistent with an earlier Chinese study, published back in June. At first, this would seem to suggest that people could be infected repeatedly or that a vaccine won’t provide long-term protection. That may be premature, however, since declines are to be expected and declining doesn’t necessarily mean going away. After all, your body doesn’t need coronavirus-neutralizing antibodies if it has not been infected by the novel coronavirus. That said, a more durable antibody response would be reassuring. The longer the initial antibody response, the more durable it generally is, but just because you don’t have any measurable antibodies doesn’t mean that you don’t have any immunity. Remember, even after the antibodies fade, memory B-cells, if they persist, can quickly replenish antibody levels in response to another infection. Unfortunately, we still don’t know how many neutralizing antibodies you need to be protected against COVID-19.
Maintaining homeostasis is essential to overall health and well-being. Homeostasis is the ability of the body to maintain a stable internal environment despite changes in external conditions. Controlling such things as body temperature, blood glucose (sugar) levels, and immune responses are among the ways the body works to control homeostasis.
As we learned, the immune system acts to prevent infections but the absence of foreign invaders must be muted. Maintaining a balance between immune tolerance and immunogenicity is required for the maintenance of immune homeostasis and requires modulation by the endocannabinoid system (ECS). For every action, there is a reaction, however in this case the reaction is less equal. In the battle of the immune system, the immune system must always win. If the immune responses are delayed due to delayed detection of the foreign invader, then so too is the adaptive response and finally, the final response delayed. Ultimately the immune system is downregulated and the body returns to homeostasis.
To ensure that our ECS is functioning optimally may require supplementation with phytocannabinoids such as cannabidiol (CBD). As our global modulator of homeostasis, maintaining a healthy ECS helps our bodies to maintain homeostasis across all our physiological systems.
So while we all wait, and learn, protecting ourselves as we can by wearing masks, practicing good hand hygiene and staying away from crowds, we can rest assured that smart people who understand the elegant complexity of the immune system are hard at work teasing apart the complex interactions and responses to the novel coronavirus getting us closer to more effective treatments and eventually an effective vaccine.