How the Immune System Works

May 8, 2020

We really don’t think about the immune system in quite the same way, in part because it’s such a mystery.

The immune system is a ridiculously complex, integrated network of specialized cells, organs and plasma proteins that we call lymph that work together to protect us from invading infections and cancers. The immune system, takes a backseat to other body systems like the cardiovascular system or the nervous system or the digestive system. We really don’t think about the immune system in quite the same way, in part because it’s such a mystery.

Well, I’m here today to bring to you a discussion of the immune system, take out some of the mystery and perhaps help you better understand some of the dynamics of the COVID-19 coronavirus pandemic.

The immune system has two components. The first component of the immune system is called innate or natural immunity. It’s the components, or the constituents, that we develop during embryogenesis in fetal development and those we’re born with. These specialized organs constitute the very foundation of the immune system.

First, there’s the barriers – the skin, mucus membranes, the lining of the G.I. and respiratory tracts. There are major organs associated with natural immunity – the spleen, the thymus gland and the bone marrow. The spleen and the thymus gland in particular help develop another component called plasma proteins, also known as lymph, which contain complement substances to help make the whole system work better.

The bone marrow in particularly is interesting and important. The bone marrow makes monocytes to protect us against invading tuberculosis, the bone marrow makes neutrophils to fight off bacterial infections, the bone marrow makes lymphocytes which fight and destroy viral infections and finally, the bone marrow is important in the development of cells called macrophages which engulf and digest particles left over from the destruction of viruses and related cells through the infectious process.

The second component of the immune system is called acquired or adaptive immunity. Unlike natural immunity, acquired immunity has memory. Think of it little bit like a computer that perfects and embellishes innate immunity – makes it work that much better to fight off infections and perhaps invading cancers.

Also distinct from innate immunity is the acquisition of acquired immunity. That is how we develop it. I told you that innate immunity is about the organs that mature during fetal development – the organs that were born with. When it comes to acquired immunity, it does not begin to develop until the birthing process. That’s right! During birth, during the passage of the fetus down the birth canal, the fetus takes in microorganisms from the mother’s vagina, to initiate the development of acquired immunity.

We call this the microbiome and it’s totally fascinating how we begin to develop acquired immunity during the birthing process, and that our mothers give us this fabulous mechanism to develop acquired immunity that we utilize through our entire lifetime!

That said, adaptive or acquired immunity matures and develops in response to infections and vaccines throughout childhood and adulthood to perfect its ability to ward off infections and to ward off cancers.

But wait! It has even more fabulous components. It has what we call B lymphocytes. B lymphocytes make antibodies to fight infections. Antibodies are a part of the memory system that I’ve talked about. When you get an infection you develop antibodies and those antibodies remember same or similar germs so that they are more readily adaptive to the infection fighting process.

Adaptive immunity also has what we call T- lymphocytes. T lymphocytes are killer cells that gobble up and destroy infected cells and the remnants of viral and bacterial infections. Finally, there are the plasma proteins that complement the overall process of immunity between both components to coordinate them and make the whole system work that much more effective and available for infection fighting.

So there you have it. I’ve explained and described the immune system as a ridiculously complex and integrated network of organs and tissues and fluids that protect us against infection and invading cancers. I’ve described the innate component of the immune system. The organs that we are born with – the  spleen, the  thymus and the bone marrow. I’ve explained acquired immunity. Acquired immunity is different from innate immunity because it has memory it can remember prior infections and respond to them to improve immune function.  

When it comes to the memory component, it’s also a segue – an entry into discussing what this COVID-19 coronavirus is all about. It is a pandemic and there are some really important reasons why it’s defined as a pandemic. First off, it’s worldwide – it’s spared almost no country because it spread so rapidly.

And we wonder why it has spread so rapidly.

First, it’s a very virulent virus, but more important than that, remember that it’s a novel virus – a  first exposure virus – so our immune system has no memory for it.  Because it has no memory, the adaptive component cannot respond rapidly to embellish innate immunity and other components of the immune system to ward it off and to fight it. It also has a very high affinity for humans, so it rapidly infects anyone who’s exposed to it.

In addition, it’s important to understand that immune system function is dependent upon nutrition. Malnutrition is prevalent worldwide. When people are malnourished their innate immune system is not as effective, it’s not as healthy, so the innate immune system is impaired in the individuals who are malnourished and lacking memory or acquired immunity as in COVID-19, it is a devastating process, there’s just no question about it.

So it’s pandemic because of no memory to the this novel virus, because it’s virulent,  because it has a high affinity for humans and because malnutrition is a worldwide phenomenon.

Here this is well. There is no better treatment for COVID-19 coronavirus than social isolation, quarantine and social distancing. For gosh sakes understand that if you’re not exposed to COVID-19 coronavirus, you can’t get infected with it. It’s as simple as that.

So obey CDC recommendations regarding it. Stay out of emergency rooms and hospitals and stay out of other congregations of individuals who might be exposed to the virus and unknowingly spread it to you.

Finally, get this. Despite messaging from media, there is no opportunity for developing an FDA approved medication or vaccine for at least a year. There’s nothing right now in the pipeline that could become available in a month or two to treat this and put it down.

This is Dr. Jim for Be Healthy! Be Happy! Stay safe. Stay isolated. Stay close to your family and your loved ones. And I’ll see you next time on Be Healthy! Be Happy! with Dr. Jim.