Immune System
Your immune system is far more than just a defense against viruses and bacteria—it's your body's ultimate cleaning force and coordinates nearly all vital functions. Discover how to strengthen your immune system through targeted training.
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At this point, we want to briefly thank you for the past year. Without our many readers and without the feedback, which is often very motivating, edubily could not exist as it does. We see this as a symbiosis and are very grateful for this constructive collaboration. For the new year, we wish you only the best, especially good health!
As a small surprise, we've uploaded our audiobook Stoffwechsel verstehen (Understanding Metabolism) to Spotify and Apple Podcasts to make it easily accessible to everyone. Enjoy listening, whether during sports, cooking, walking, or ironing.
Now to the topic: Have you ever imagined what the world would look like or how it could even function if there were no police, no garbage collection, no disaster relief, no firefighters, no doctors or nurses, no social workers or mediators, and no cleaning crews? Exactly: the world would be complete chaos. What we find at the macro level—in the world—also exists at the micro level.
When we think of our immune system, we often think of pathogen defense. If someone "has a good immune system," they rarely get sick because this potent immune system apparently quickly and powerfully destroys viruses, bacteria, and the like. What most people don't realize is that the immune system combines all of the above factors (firefighters, police, etc.) in one. Without the immune system, we wouldn't just be unable to survive because even the most harmless fungi would kill us. Our immune system is the ultimate cleaning force of the body that keeps us clean and functional in every way.
The brain enjoys a special immunological status in the body because brain cells are inherently sensitive. Therefore, antibodies and other immune cells can't simply enter from the blood. Nature has developed highly special and impressive cells called microglia for this purpose. When activated, they move through nerve tissue in the shape of an amoeba and kill pathogens there, for example. Even more importantly, they simply engulf cellular debris that nerve cells "put out the door" and thereby eliminate it. This is the only reason we can "think clearly."
What hardly anyone knows: muscles can only grow and function because immune cells coordinate this: After exercise, macrophages—the immune system's scavenger cells—dispose of the resulting cellular debris. They activate muscle stem cells at the same time, which need to heal and grow. As a result, T cells accumulate in the muscle, which simultaneously triggers a change in the shape and function of macrophages, turning them into so-called M2 macrophages. They suppress inflammation, relieve pain, and thereby promote healing. Additionally, this stimulates the differentiation of muscle stem cells and the formation of connective tissue. All of this is further boosted by the fact that macrophages also release the growth hormone IGF-1. (Cf. current study from University of Heidenheim)
Isn't that impressive? In this or similar ways, the immune system ensures functional maintenance in virtually all tissues of the body—and what about species preservation? The immune system could even be responsible for the functional maintenance of society as a whole. Cells present themselves to the immune system using so-called MHC proteins. They function like an ID card containing specific information about the cell's interior. This way, the immune system always knows what's happening in the cell: does the cell belong to me, or does it contain pathogen material?
Researchers believe they know that our counterpart can "smell" this information. In this way, partner selection is supposed to be influenced to increase the likelihood of healthy offspring. One thing is clear: a fit immune system is the key to a healthy life. One might ask: when we can't "stand the smell" of someone, could our immune system have had a say in that?
As suggested recently, even the best system in the world has its weaknesses. Like everything in biology, the immune system must make compromises and walk a fine line—in the case of the immune system, it's about achieving the perfect balance between destroying and healing. Deviations or disturbances in this balance can cause the immune system to develop autoimmunity or cause allergies. Take antibodies as an example. Why do many people suddenly have auto-antibodies in their blood during or after contracting COVID?
We have a whole range of different antibodies in us. Some work very specifically, others rather broadly. The latter increases the likelihood of so-called cross-immunity. This happens when an antibody can not only bind to one target but recognizes similar sequences and can thus also bind to other targets. What many don't know: most of us have developed auto-antibodies at some point in our lives—antibodies that also react against our own body's tissue.
During an infection with a pathogen the body doesn't know well—as with SARS-CoV-2—antibodies rise dramatically that cross-react with the pathogen, meaning they recognize many possible binding sites. The probability that these antibodies then unfortunately also react against "self," that is, against our own tissues, is high. At this point, a fundamental principle of biology becomes clear: survival first, health second. It sounds like a contradiction, but survival is about fighting off the virus—health is more about not developing autoimmunity, which would make us sick in the long term.
The good news: when the immune system comes back into balance—for example, when it produces specific antibodies against the virus—the need for cross-reacting antibodies becomes obsolete. They decline, and we may never notice anything from it.
Humans have been in contact with countless microbes daily for many millions of years. These include fungi, bacteria, other single-celled organisms, and viruses. We're even colonized by an enormous number of these microbes—especially in contact with mucous membranes, such as in the mouth but especially in the gut, where a delicate balance must be maintained between "defense" and "tolerance." A largely perfect symbiosis develops that provides benefits for both sides. By now, it's well-established that our immune system needs this contact with microorganisms to properly calibrate itself.
In addition, in constant contact with other people, we continuously infect ourselves with small amounts of, for example, viruses. There are times of the year when, in perhaps 80, 90, or even 99 % of people, one would find cold or common coronaviruses on the mucous membranes—certainly without us actually becoming ill and developing symptoms like a cold. Many people don't realize that "infection" doesn't mean "disease." In fact, we can assume that constant contact with ordinary, endemic viruses is necessary to have a normally or well-functioning immune system:
The immune system is so "trained" after contact with viruses and the like that it then reacts much more powerfully and aggressively to future infections: "Like a soldier or an athlete, innate immune cells can be trained through prior experience so they can fight infections better," said lead author Quen Cheng, an assistant clinical professor of infectious diseases at the David Geffen School of Medicine at UCLA. (Q)
Cross-immunities develop, with the body being able to better recognize and more quickly neutralize other, similar viruses after contact with, for example, a particular virus type: "Certain immune cells that people have formed against cold coronaviruses in the past strengthen the immune response against SARS-CoV-2—both during natural infection and after vaccination." (Q, Q)
Acute, though mild, infections of the mucous membranes trigger a systemic immune response that protects against further infections, even by other pathogens. Constant contact with pathogens activates the immune system and makes it more "alert"—possibly a reason why children handle SARS-CoV-2 much better than adults.
How well such "training" works is demonstrated by the "super immunity" observed in people who first received the SARS-CoV-2 vaccine and then were infected (breakthrough infection). Not only did the number of antibodies increase—they were also significantly more powerful, up to 1,000% more effective. (Q) Of course, this by no means means we approve of deliberate infection.
The key difference in the thinking of many people is: some see death or severe illness in an infection. True for rabies. Partly true for COVID, but also for severe flu. Depending on the immune system or immune status—for example, in cancer patients—this can also apply to the mildest pathogens. Other people see daily contact with viruses and the like, particularly through transmission by other people, as the most important way to "strengthen" the immune system, to train it, and to keep it combat-ready—see above.
Fact is: you should always keep in mind a biological principle that says: use it or lose it. This applies not only to an atrophied or hypertrophied muscle; it also applies to the brain ("brain jogging"), to bone, and… exactly… to the immune system. Train it! It will thank you for it.
In any case, the immune system seems to control more than we realize. By the way: we repeatedly point out that milk and milk products contain tiny fat globules, so-called exosomes, that transport, for example, mRNA, miRNA, proteins, enzymes, and DNA or nucleic acids. Researchers believe these exosomes are nature's most ingenious invention. This is because these exosomes are resistant to digestion, reach cells in our bodies, and are bioactive there. Therefore, researchers want to use these milk exosomes to smuggle drugs and the like into the body in the future.
Milk and milk products regulate the offspring's immune system in this way. Very current research gives us insight into how this could affect things:
If there is a powerful tool that could significantly affect the immune system, it's milk and products made from it. To what extent it makes sense for an adult mammal to drink milk from another species remains to be seen. The fact is that in some situations it could be very beneficial, in others perhaps less so. Milk and its factors seem in any case to have a rather immunosuppressive or anti-inflammatory effect. (Cf. Latest Trend of Milk Derived Exosomes: Cargos, Functions, and Applications)
The immune system is a miracle, and there will be many more facets to discover. In addition to insulin resistance (last newsletter), we should pay more attention to our immune system in the new year. It's really not that difficult:
If your immune system is built on this foundation, it is tolerant (little autoimmunity, few allergies) and protects you promptly (!) against infection. Because once we're severely infected, it's too late. We need to take care of it beforehand. Oh yes: and perhaps we'll also meet the right partner. Good prospects for the new year.
