Immunology 101: Improving Your Immune System


I am going to provide you with credible and tactical information that is going to help you stay safe and healthy. I will share what I have learned about the Integrative/Functional Medicine approach to COVID-19.

Let's start with Immunology 101. We will learn the basics and how COVID-19 virus uses our cells to invade, then go into how botanicals are therapeutically used to combat this coronavirus.

The First Step is what we are all doing: Following public health measures to decrease viral transmission, social distancing, washing hands, not touching your face or eyes-this will help to flatten the curve.

Second Step: Optimize your lifestyle to improve the overall function of your immune system.

The Third Step: Inhibiting the virus from causing a massive immune response.


We have two arms of the immune system- the Innate and Adaptive immune system. They are not quite as distinct, with the main difference being that the innate response is nonspecific, meaning it doesn’t require prior exposure, and COVID-19 is a brand new virus our immune systems have not seen before.

Innate immune systems have two components. First, the barriers or mucus membranes, cilia, PH... all these are acting to keep the virus away. There are a lot of different cells involved in this first response. Such as macrophages, monocytes, natural killer cells, all complementary systems.


As we now know that COVID-19 is an RNA virus, we've learned it has a few important proteins that it uses to enter our body. These are called the S-protein – or the spike protein, the envelope protein, the membrane protein, nucleic acid protein...this S-protein looks like a spike on the outer surface of the virus. This S-protein binds to the ACE2 receptor and finds its way inside the human body. ACE2 is protective of the respiratory systems and its receptors are present all over the body but most prevalent in the respiratory tract.  ACE2 cells produce surfactants. What happens when COVID-19 enters the cells is the ACE2 cells stop producing the surfactant.

ACE2 receptors are found on the macrophages and dendritic cells (cells in your first response, aka innate immune system). Both the macrophages and dendritic cells have receptors that are called 'Toll-like receptors'. The most important receptor for COVID-19 is the Toll-like receptor or, TLR-9 for short. TLR-9 is not the only receptor, but in this virus, COVID-19, it is a critical receptor.

When the virus gets into the cells and starts replicating, it simultaneously activates the TLR-9 receptor. Once this receptor is activated, it will produce an inflammatory storm. The primary two compounds are produced NFkb and Type 1 interferon.
Type 1 interferons are the compounds that start to fight off the virus. This step is happening before the second arm of the immune system's adaptive immune system starts to make antibodies against the virus.

Hang in there...this is a complex topic!

The second critical step of the virus binding, is the cell receptor called the 'NOD receptor' specifically, NLRP3. Activation of NLRP3 is very important for us to fight off the virus. So there are two important receptors, TLR9 (this one is outside the cell) and NLRP3 (NLRP3 is located inside the cell). This is an important defense mechanism against COVID-19 and very important. When NLRP3 is activated, it leads to the production of Interleukin 1 beta. Interleukin 1 beta starts fighting off the virus.

Like all things in moderation, we need a little bit of Interleukin 1 beta, because a lot of it can be harmful to us. It is a potent pro-inflammatory cytokine, which are a large group of proteins that help to mediate and regulate immunity. We want our immune system to respond so it can recruit other immune cells such as Natural Killer, or NK cells. Natural killer cells identify the cells infected with the virus and eat them up. However, we do not want our immune system over-activated, potentially leading to what we see in the severity of COVID-19 cases with what is referred to as a 'cytokine storm'. This is why I always recommend you work with a doctor who can monitor you.

What does this all mean?

You have been hearing that 80 percent of people get mild symptoms or no symptoms at all from COVID-19. These people have an innate immune system that is working just right and taking care of foreign invaders. When the virus fails the innate immune system you start to see the more severe impacts of COVID-19.

What we want to start doing is to support our innate immune system, so that our innate immune system produces the right amounts of cytokines and chemokines to destroy the virus. We do not know why some people get the cytokine storm and others do not. Is it the immune system, the viral load or viral strain? We just do not know. We do know that it’s the activation of NLRP3 which leads to the progression of the inflammatory storm.


Curcumin: Curcumin is the yellow pigment found in turmeric. It’s a polyphenol. What are polyphenols? They are micronutrients you get from eating certain plant-based foods and they’re packed with antioxidants. And antioxidants are compounds that inhibit oxidation, which creates a chemical reaction that can produce free radicals or unstable atoms that can damage cells and trigger inflammation.⁠

Free radicals and their oxidative process can accelerate viral mutations. Curcumin has been shown to modulate the hyperinflammation caused by COVID-19. And early research suggests that curcumin can target the COVID-19 main protease, or enzymes, to reduce viral replication.⁠

While curcumin is found in turmeric, it can also be extracted to make supplements that have a higher potency than turmeric. Suggested dose: 500-1,000 mg by mouth twice per day (of absorption-enhanced curcumin)⁠

Quercetin: One of the most abundant antioxidants in your diet, quercetin is present in the pigments of many fruits, vegetables, and some grains. It has been shown to have antiviral effects against both RNA (e.g., influenza and coronavirus) and DNA viruses (e.g., herpesvirus).⁠

It shows moderate evidence for reducing symptoms and its mechanism for action against COVID-19 may promote viral eradication or inactivation, inhibition of viral replication, promote resolution of inflammatory damage and restoration of immune function.⁠ Suggested dose: 1000mg twice daily

Melatonin: Research is in progress showing favorable inhibitory effects on COVID-19's inflammatory properties. Two recently published papers have proposed the use of melatonin as a therapeutic agent in the treatment of patients with COVID-19.⁠ Suggested dose: 5-20 mg per day⁠

EGCG: (compound from green tea) - In addition to reducing inflammation, green tea enhances the immune system and targets one of the processes involved in COVID-19 replication. Suggested dose: 4 cups of organic green tea or 225mg of the extract EGCG daily

Resveratrol: a compound found in red grapes, has many beneficial health effects and has been shown in the lab to attack a relative of the COVID-19 virus. Suggested dose: 100mg twice daily

I hope this information has been helpful to you! I encourage you to eat whole foods, increase your green leafy vegetable consumption and have an active lifestyle.

Stay safe and healthy.

Lots of love,

Dr. Grewal

"My goal is to share my knowledge with the world. I believe in delivering valuable and ethical content that changes the lives of my patients." -Kiran Grewal MD



Joel Evans, MD (Lead), Robert Rountree, MD, Tom Guilliams, PhD, Michael Stone, MD, Robert Luby, MD, Patrick Hanaway, MD, Kirsten Ramsdell, MS, CN, Sam Yanuck, DC, Helen Messier, MD, and Dan Lukaczer, ND,
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