How the Defense System of the Body Takes On Viruses
We constantly encounter microorganisms that could harm our health. The immune system of humans constantly defends us against these fears for our survival. Understanding how immunity works are important for making sense of the news around the risk, spread, and treatment of diseases like COVID-19.
You’ve perhaps heard that your best defense against the coronavirus is practicing social distancing, washing your hands, and having a healthy immune system. A dysfunctional immune system is one reason that COVID-19 has proven more deadly in people with certain pre-existing conditions and in older adults. On the other hand, it’s not continually that the immune system is weak because at times the body’s immune response is dominant that it ends up killing COVID-19 patients.
How Does The Immune System Normally Respond To A Virus?
The first immune response is very fast. You have immune cells that sense the virus as a strange agent, and they begin to make a lot of things called cytokines to stop the virus. Several of these cytokines kill cells to keep the virus from duplicating. One cytokine is IL-1beta which turns your temperature up. A lot of viruses die at high temperatures, so your body gives you a fever. This response is called innate immunity. The adaptive immunity is a more specific response to this particular invader to try to clear it. B cells generate antibodies, and T cells help B cells make antibodies and can kill viruses themselves. If everything goes well, you will kill the virus and you will develop some immunity to it.
How do obese and diabetic people affect your immune response to a virus?
Diabetes and obesity are intensely associated with a dysfunctional immune system. If you take a gaze at the fat of an obese person, you will find a reservoir of T cells that make tons of these cytokines. As a result, they are at increased risk or most have higher levels of pro-inflammatory cytokines.
The fact that they already have a high baseline means that they may not have the suppressive function to turn off that inflammation if they need to. So, if they get an extra hit, it will be harder to stop. They are already one level closer to this cytokine storm.
Older Adults and Their Immune System
As a person gets older, both the adaptive and the innate immune cells are not as able at increasing a response to an infection.
In the innate immune cells, pathways that make cytokines don’t work properly. It takes them longer to make the cytokines and by that time the pathogen may have already invaded other cells. At the same time, the innate immune cells don’t communicate as well with the adaptive immune cells to mount that second line of defense.
Another important thing is that the immune cells are all derived from stem cells in the bone marrow. And as you age, your bone marrow has a smaller pool of those cells to draw on and impacts how many immune cells you produce.