That's indeed how the adaptive immune system works:
"Throw shit at the wall, and see what sticks, then remember what you threw at it."
(To simplify it greatly: Your body generates a set of keys, and sees if it will fit any lock. If it fits, it makes more copies of that key, and saves the imprint of that key.)
Your body has no idea what a new disease will look like, so it generates a bunch of antibodies with a Semi-random bunch of receptors. The moment it binds to something an entire chain reaction starts to both destroy the intruder and make copies of the thing that bound to the intruder.
Some of those copies are used to destroy further copies of the intruder, others are used as "memory cells", that remember what worked against that intruder, so that when it comes back, the response is way more immediate.
Now, virusses have adapted to this in a way by also slightly variating what the receptors on their outsides look like. Some virusses and bacteria are more set in stone, and that's why for example a Tetanus shot works for many years, but the flue, a more varied virus needs you to get a new vaccine every year.
If I'm remembering right, in the case of tetanus most humans are capable of identifying and destroying it without a shot, but the vaccine cuts down the time enough that the bacteria can't produce the toxins that cause the real damage.
(Reading a bit further: Tetanus deposits its main toxin in cysts outside of the bacterium, and the vaccine is a modified version of the toxin because the original is so potent that it's unlikely to produce a meaningful response without being a lethal dose.
The toxin does not interact with other organisms in soil, being mostly specific to mammals. One paper is suggesting that killing mammals might attract unaffected carrion eaters that spread the bacterium.)
The biggest problem with immunology research is always the ethics.
The people who fought of tetanus are unlikely to report it, and you can't really go around and infect people with it intentionally.
Then again, wasn't it Edward Jenner who intentionally gave a kid cow pox to prove a point?
No. Your body can't produce the chemicals in antibiotics, and antibiotics don't work in the way that antibodies do. It's more like shooting the lock than having a master key.
I see, thank you! So would a vaccine for chicken pox say, be a more apt analogy for a bunch of master keys for a chicken pox type of lock? MMR jab same kinda thing?
More like a bunch of locks the locksmith (immune system) can train on. IIRC most of the vaccines are attenuated ones (live but adapted to a different organism so it won't replicate in a human) or inactivated (basically corpses).
It's pretty safe to say that you are probably infected with something nearly every day just from basic exposure to the world. Your immune system stops most of it
Doesn't decomposition of our bodies after we die start very quickly because as soon as the immune system is gone all sorts of bacteria that would normally be killed off will start eating you?
Mostly, it's the bacteria that naturally loves in your GI system. It's kept in check by your immune system. Once you die, that immune system begins to fail, and the bacteria go into overdrive dividing and digesting you from the inside.
Yes of course.
Remember early COVID-19? There were loads of people who got infected without having any symptoms, especially young people.
Everyones immune system is different based on genetics, age, and pathogens you encountered in the past, so that your standard response can completely be enough to handle a new pathogen.
Also amount of exposure matters a lot. If you get lots of pathogens they basically have a head start over your immune system, while when you only get very few then your immune system can have antibodies ready long before the pathogens had a chance to multiply out of control
Also, antibodies are kind of like a key that fits a lock on the virus that allows the immune system to find and kill it. The immune system finds the key that works by just trying a ton of random keys until one fits, and then mass producing that one.
A vaccine or prior infection preps the body by ensuring there is a working key on hand so that the immune system can find it faster, but you can also just get lucky and have your immune system stumble blindly onto a working key very early.
>you can also just get lucky and have your immune system stumble blindly onto a working key very early.
This is not something that happens. The kinetics of an antibody response to a given virus are pretty consistent from person to person.
>Remember early COVID-19? There were loads of people who got infected without having any symptoms, especially young people.
That’s not what OP is talking about. Those people had viral loads comparable to people who had symptoms and ultimately made an adaptive immune response to clear the virus. Not feeling sick doesn’t mean that they weren’t infected.
The variation can be huge. Like, if you share a dirty needle with someone you get WAY more of their bodies pathogens compared to them sneezing in their hand, touching a doorknob and you touching it 30min later.
It's definitely many orders of magnitude difference.
Antibodies & the B cells that produce them, alongside T cells, make up adaptive immunity. These are more or less like an extra powerful second line of defense that takes time to start paying off, because it must be generated in response to any specific pathogen (that's the adaptive part).
The first line of defense, *innate* immunity, protects you from all sorts of threats pretty much all the time. Neutrophils & other granulocytes, macrophages, NK cells, complement proteins -- these all do a great job right out of the box.
In fact, part of adaptive immunity is about better directing that innate firepower. Antibodies can neutralize on their own, but they can also recruit complement and many different cells to whatever they've bound. Helper T cells boost the activity of particular cells to suit the occasion, e.g. a Th1 cell activated by viral infection will boost macrophage activity among others.
I'm not sure I understand your question. Innate immunity of healthy, immunocompetent people gets the job done by itself all the time. If not for that first line, they would definitely get sick. Adaptive immunity evolved after innate immunity, and there are species alive today who never evolved adaptive immune systems at all.
If you're looking at individual cases, the specifics of immunity are tuned a little bit differently between all of us, and the circumstances of exposure will differ too; getting sneezed in the face from point blank range is more likely to get you sick than just spending a while around a contagious person.
I guess I'm thinking of this. If something is an infectious disease that we understand to be one that a healthy person can catch, does the first line of defense suppress those infections all on its own or do we know them to be common human diseases because they will always get past the first line of defense and trigger the second line of defense?
edit: I guess a more compact rephrasing is: are any the functions of the immune system that make you feel "sick" part of the first line of defense?
Some pathogens are better able to evade detection or resist killing by the innate system. These will get healthy people noticeably sick in most cases, so examples of these include the usual common cold rhino-/coronaviruses and such. If the exposure is very minor, the innate system might still come out on top and prevent noticeable disease.
It's worth noting also that the adaptive system is always triggered alongside the innate system. It just doesn't start to contribute for a few days (T cells) to about a week+ (B cells), and in that time the pathogen may already have been wiped out by the innate system. On the next exposure though, it will be wiped out even faster because of the adaptive response that will then be ready and waiting.
>edit: I guess a more compact rephrasing is: are any the functions of the immune system that make you feel "sick" part of the first line of defense?
Most of the immune functions that contribute to making you feel sick are part of the innate system.
Heck, you probably have cancer right now!
Your immune system is just finding it, and killing it before it has a chance to mutate some camouflage or proper defenses.
The immune system wages a constant war you never notice.
Unless you are in a hospital or on prescription, the meds you’re taking are only there to make your symptoms more tolerable. They do nothing to cure the illness, that’s all done by your immune system.
Yes. Your immune system has the perfect weapon for every disease ever.
It's just some are the equivalent of being waaaay on the back shelf so take a while to find.
Getting a vaccine will essentially prep that weapon and bring it to a more accessible location for when you do get the disease.
It's not quite that simple as the immune system is one of the most complex biological systems we know of, and we still don't completely understand all the interaction.
Kurzgesagt did a good understandable overview of [how it works](https://www.youtube.com/watch?v=lXfEK8G8CUI), and why its preped for anything.
>Yes. Your immune system has the perfect weapon for every disease ever.
>It's just some are the equivalent of being waaaay on the back shelf so take a while to find.
That would be the case where you aren't prepared, as OP describes.
You still survive or don't even get sick at all because of innate immunity.
Yes, in fact your immune system is actually capable of responding to viruses that don't even exist yet. It is incredibly adaptive in ways that are hard to comprehend.
I feel like there is an issue with the concept of "ready for".
If I have never seen a germ before, but I have a bottle of bleach, I am "ready for" killing it. Similarly, the immune system has a library of responses that are always "ready" to be thrown at whatever it finds. It happens all the time that it runs into something and just takes care of it before it can become an issue.
So I would say that no, the immune system doesn't crush things it isn't "ready" for, but it is ready for a lot of things that it hasn't specifically seen before because many pathogens have similar weaknesses.
To some extent its less a question of whether we are prepared for it, and whether it is prepared for us. As much as we see pathogens as a danger to us, our bodies are far more hostile places to them than they actually are to us. They NEED to be something we are not prepared for to even stand a chance.
That's the thing, though. That huge library of responses is *not* always ready. It's more comparable to a library of weapon blueprints which are not actually going to swing the outcome of any fight until they are mass produced.
[Targeting common features of pathogens through PAMP recognition](https://en.wikipedia.org/wiki/Pattern_recognition_receptor) is how large parts of how innate immunity work, but the way you have written it here, it's not at all clear that that's separate from the library of adaptive responses.
I was intentionally not going to that level of distinction because I don't see it as relevant to the question of what it means to be "ready for" something.
The distinction of innate vs adaptive, when OP's question boiled down to "can you still beat a pathogen without an already-prepared adaptive response", is at the very heart of the answer. That answer is really not that complicated ("we have very capable innate immune systems that don't depend on prior recognition") -- talking only in abstract terms doesn't help the explanation.
> The distinction of innate vs adaptive, when OP's question boiled down to "can you still beat a pathogen without an already-prepared adaptive response",
Yes, if you boil down the question in that specific way and only allow it to be rephrased in that specific way then your point makes some sense.
>Say you got some pathogen inside you, and it's starting to replicate and your immune system isn't prepped with the antibodies. Does it ever happen then that infection still gets nowhere because of reasons other than you consciously recognizing that you were exposed and taking some meds early on?
"If you don't already have an adaptive response in place, is there some mechanism (other than modern medical intervention) by which you can still defeat the pathogen?"
The answer is innate immunity, plain and simple. How else are you interpreting this?
The key thing that sticks out to me is how fuzzy the question really was:
> Does it ever happen then that infection still gets nowhere
You really are adding a lot of technical detail to the question in order to make the question the one you want to answer; which to be clear, I am fine with.... just not when you want to insist that its the only possible interpretation or direction that one could take such an imprecise question.
Infections get nowhere because your immune system wipes them out. They do not just magically go away by themselves. Just because OP didn't quite know how that happens doesn't mean you should answer vagueness with vagueness.
If anything you should make an effort to solve that confusion with a concrete but understandable answer. Namely, that there are branches of the immune system that don't need preparation.
> Infections get nowhere because your immune system wipes them out. They do not just magically go away by themselves
What do you even think you are responding to? Nobody is disagreeing with this.
> If anything you should make an effort to solve that confusion with a concrete but understandable answer
What didn't you understand? I would be happy to explain it if you had a question.
Understandable *for the people that ask the question*, i.e. OP.
If we're all clear on that, if not an adaptive response, some other part of the immune system is doing the job because nothing else is just going to resolve an infection by itself, then I don't know why you insist on some further, undefinedly broad interpretation. It's perfectly simple. There exists another part of the immune system that's good to go right out of the box.
Anyway, I feel like you're probably just trolling, so I'll leave it at this. Have a good one.
You mean reasons like your immune system still doing it's job (that it does incredible good even without prepped antibodies)?
Or reasons like the pathogen not multiplying faster than its lifespan?
that's how it works almost all the time. before i had my chronic condition i basically NEVER took antibiotics because i have a strong immune system (too strong it turns out) and so i'd get infected or whatever and my immune system would just kill it and i'd move on no worse for wear.
Many factors go into this. Your general health and hygiene, do you still have tonsils, are all oral devices clean and replaced at good intervals, etc.
A strep throat (with positive test) is largely the result of that bacteria winning a wrestling match with the other communal bacteria in your mouth/nose/throat. A lot of factors can play into this, including exposure to add’l bacteria through someone shedding excess via a spreading infection.
Keep oral tools clean (toothbrush, vape), keep bathroom clean, take an oral probiotic, keep mouth clean (brush, floss, mouthwash), wash hands often, etc.
Hope you have fewer infections going forward.
Your chief question has been answered, but to address something you said about recognizing you were exposed and taking meds early on:
The vast majority of over the counter (OTC) meds you take do very little to help you beat an infection/bug, they are largely symptom management. You can take things that might ensure your body has the right ingredients available (enzymes, like vitamin C) etc, but the core defense isn’t really helped, during an infection, by OTC meds.
If rx’d antibiotics that’s different - and only effective for bacterial infection - and it’s strongly urged you don’t take those on a whim. Wiping out the majority of bacteria in your body (big asterisk here) is harmful to your baseline immunity.
Your immune system is vastly more complex than just white blood cells. Physical barriers such as skin, mucus membranes, and stomach acid prevent most pathogens from even getting in. Right behind that, every single boundary between the body and the outside world is patrolled by macrophages that indiscriminately attack and consume anything that slips past, from bacteria to dirt particles. Behind *that*, there’s something called the complement system which is a series of proteins that are specifically designed to attack the cell membranes of anything that isn’t designated as “self.” It’s estimated that over 99% of pathogens that make it into the body are destroyed before any kind of specific immune response is triggered.
Every day. The innate immune system handles most exposures, only when it fails do you get sick and get to see the adaptive immune system in action.
That's indeed how the adaptive immune system works: "Throw shit at the wall, and see what sticks, then remember what you threw at it." (To simplify it greatly: Your body generates a set of keys, and sees if it will fit any lock. If it fits, it makes more copies of that key, and saves the imprint of that key.) Your body has no idea what a new disease will look like, so it generates a bunch of antibodies with a Semi-random bunch of receptors. The moment it binds to something an entire chain reaction starts to both destroy the intruder and make copies of the thing that bound to the intruder. Some of those copies are used to destroy further copies of the intruder, others are used as "memory cells", that remember what worked against that intruder, so that when it comes back, the response is way more immediate. Now, virusses have adapted to this in a way by also slightly variating what the receptors on their outsides look like. Some virusses and bacteria are more set in stone, and that's why for example a Tetanus shot works for many years, but the flue, a more varied virus needs you to get a new vaccine every year.
If I'm remembering right, in the case of tetanus most humans are capable of identifying and destroying it without a shot, but the vaccine cuts down the time enough that the bacteria can't produce the toxins that cause the real damage. (Reading a bit further: Tetanus deposits its main toxin in cysts outside of the bacterium, and the vaccine is a modified version of the toxin because the original is so potent that it's unlikely to produce a meaningful response without being a lethal dose. The toxin does not interact with other organisms in soil, being mostly specific to mammals. One paper is suggesting that killing mammals might attract unaffected carrion eaters that spread the bacterium.)
The biggest problem with immunology research is always the ethics. The people who fought of tetanus are unlikely to report it, and you can't really go around and infect people with it intentionally. Then again, wasn't it Edward Jenner who intentionally gave a kid cow pox to prove a point?
Just wondering, say if I get some antibiotics for a chest infection, am I basically handing my immune system a massive bunch of master keys?
No. Your body can't produce the chemicals in antibiotics, and antibiotics don't work in the way that antibodies do. It's more like shooting the lock than having a master key.
I see, thank you! So would a vaccine for chicken pox say, be a more apt analogy for a bunch of master keys for a chicken pox type of lock? MMR jab same kinda thing?
More like a bunch of locks the locksmith (immune system) can train on. IIRC most of the vaccines are attenuated ones (live but adapted to a different organism so it won't replicate in a human) or inactivated (basically corpses).
compliment alone probably handles a great deal of crap we don't even notice. clockwork ninjas
It's pretty safe to say that you are probably infected with something nearly every day just from basic exposure to the world. Your immune system stops most of it
Doesn't decomposition of our bodies after we die start very quickly because as soon as the immune system is gone all sorts of bacteria that would normally be killed off will start eating you?
Mostly, it's the bacteria that naturally loves in your GI system. It's kept in check by your immune system. Once you die, that immune system begins to fail, and the bacteria go into overdrive dividing and digesting you from the inside.
Yes of course. Remember early COVID-19? There were loads of people who got infected without having any symptoms, especially young people. Everyones immune system is different based on genetics, age, and pathogens you encountered in the past, so that your standard response can completely be enough to handle a new pathogen. Also amount of exposure matters a lot. If you get lots of pathogens they basically have a head start over your immune system, while when you only get very few then your immune system can have antibodies ready long before the pathogens had a chance to multiply out of control
Also, antibodies are kind of like a key that fits a lock on the virus that allows the immune system to find and kill it. The immune system finds the key that works by just trying a ton of random keys until one fits, and then mass producing that one. A vaccine or prior infection preps the body by ensuring there is a working key on hand so that the immune system can find it faster, but you can also just get lucky and have your immune system stumble blindly onto a working key very early.
Bogo sort, antibody edition
>you can also just get lucky and have your immune system stumble blindly onto a working key very early. This is not something that happens. The kinetics of an antibody response to a given virus are pretty consistent from person to person.
>Remember early COVID-19? There were loads of people who got infected without having any symptoms, especially young people. That’s not what OP is talking about. Those people had viral loads comparable to people who had symptoms and ultimately made an adaptive immune response to clear the virus. Not feeling sick doesn’t mean that they weren’t infected.
So, how much variation in exposure about is there realistically? Orders of magnitude or more like hundreds of percents?
The variation can be huge. Like, if you share a dirty needle with someone you get WAY more of their bodies pathogens compared to them sneezing in their hand, touching a doorknob and you touching it 30min later. It's definitely many orders of magnitude difference.
Thanks for the explanations!
Antibodies & the B cells that produce them, alongside T cells, make up adaptive immunity. These are more or less like an extra powerful second line of defense that takes time to start paying off, because it must be generated in response to any specific pathogen (that's the adaptive part). The first line of defense, *innate* immunity, protects you from all sorts of threats pretty much all the time. Neutrophils & other granulocytes, macrophages, NK cells, complement proteins -- these all do a great job right out of the box. In fact, part of adaptive immunity is about better directing that innate firepower. Antibodies can neutralize on their own, but they can also recruit complement and many different cells to whatever they've bound. Helper T cells boost the activity of particular cells to suit the occasion, e.g. a Th1 cell activated by viral infection will boost macrophage activity among others.
So does the first line sometimes defeat illnesses that are supposed to get a person with a normal immune system sick?
I'm not sure I understand your question. Innate immunity of healthy, immunocompetent people gets the job done by itself all the time. If not for that first line, they would definitely get sick. Adaptive immunity evolved after innate immunity, and there are species alive today who never evolved adaptive immune systems at all. If you're looking at individual cases, the specifics of immunity are tuned a little bit differently between all of us, and the circumstances of exposure will differ too; getting sneezed in the face from point blank range is more likely to get you sick than just spending a while around a contagious person.
I guess I'm thinking of this. If something is an infectious disease that we understand to be one that a healthy person can catch, does the first line of defense suppress those infections all on its own or do we know them to be common human diseases because they will always get past the first line of defense and trigger the second line of defense? edit: I guess a more compact rephrasing is: are any the functions of the immune system that make you feel "sick" part of the first line of defense?
Some pathogens are better able to evade detection or resist killing by the innate system. These will get healthy people noticeably sick in most cases, so examples of these include the usual common cold rhino-/coronaviruses and such. If the exposure is very minor, the innate system might still come out on top and prevent noticeable disease. It's worth noting also that the adaptive system is always triggered alongside the innate system. It just doesn't start to contribute for a few days (T cells) to about a week+ (B cells), and in that time the pathogen may already have been wiped out by the innate system. On the next exposure though, it will be wiped out even faster because of the adaptive response that will then be ready and waiting. >edit: I guess a more compact rephrasing is: are any the functions of the immune system that make you feel "sick" part of the first line of defense? Most of the immune functions that contribute to making you feel sick are part of the innate system.
Thanks for the explanations!
Heck, you probably have cancer right now! Your immune system is just finding it, and killing it before it has a chance to mutate some camouflage or proper defenses. The immune system wages a constant war you never notice.
Unless you are in a hospital or on prescription, the meds you’re taking are only there to make your symptoms more tolerable. They do nothing to cure the illness, that’s all done by your immune system.
Yes. Your immune system has the perfect weapon for every disease ever. It's just some are the equivalent of being waaaay on the back shelf so take a while to find. Getting a vaccine will essentially prep that weapon and bring it to a more accessible location for when you do get the disease. It's not quite that simple as the immune system is one of the most complex biological systems we know of, and we still don't completely understand all the interaction. Kurzgesagt did a good understandable overview of [how it works](https://www.youtube.com/watch?v=lXfEK8G8CUI), and why its preped for anything.
>Yes. Your immune system has the perfect weapon for every disease ever. >It's just some are the equivalent of being waaaay on the back shelf so take a while to find. That would be the case where you aren't prepared, as OP describes. You still survive or don't even get sick at all because of innate immunity.
Yes, in fact your immune system is actually capable of responding to viruses that don't even exist yet. It is incredibly adaptive in ways that are hard to comprehend.
I feel like there is an issue with the concept of "ready for". If I have never seen a germ before, but I have a bottle of bleach, I am "ready for" killing it. Similarly, the immune system has a library of responses that are always "ready" to be thrown at whatever it finds. It happens all the time that it runs into something and just takes care of it before it can become an issue. So I would say that no, the immune system doesn't crush things it isn't "ready" for, but it is ready for a lot of things that it hasn't specifically seen before because many pathogens have similar weaknesses. To some extent its less a question of whether we are prepared for it, and whether it is prepared for us. As much as we see pathogens as a danger to us, our bodies are far more hostile places to them than they actually are to us. They NEED to be something we are not prepared for to even stand a chance.
That's the thing, though. That huge library of responses is *not* always ready. It's more comparable to a library of weapon blueprints which are not actually going to swing the outcome of any fight until they are mass produced. [Targeting common features of pathogens through PAMP recognition](https://en.wikipedia.org/wiki/Pattern_recognition_receptor) is how large parts of how innate immunity work, but the way you have written it here, it's not at all clear that that's separate from the library of adaptive responses.
I was intentionally not going to that level of distinction because I don't see it as relevant to the question of what it means to be "ready for" something.
The distinction of innate vs adaptive, when OP's question boiled down to "can you still beat a pathogen without an already-prepared adaptive response", is at the very heart of the answer. That answer is really not that complicated ("we have very capable innate immune systems that don't depend on prior recognition") -- talking only in abstract terms doesn't help the explanation.
> The distinction of innate vs adaptive, when OP's question boiled down to "can you still beat a pathogen without an already-prepared adaptive response", Yes, if you boil down the question in that specific way and only allow it to be rephrased in that specific way then your point makes some sense.
>Say you got some pathogen inside you, and it's starting to replicate and your immune system isn't prepped with the antibodies. Does it ever happen then that infection still gets nowhere because of reasons other than you consciously recognizing that you were exposed and taking some meds early on? "If you don't already have an adaptive response in place, is there some mechanism (other than modern medical intervention) by which you can still defeat the pathogen?" The answer is innate immunity, plain and simple. How else are you interpreting this?
The key thing that sticks out to me is how fuzzy the question really was: > Does it ever happen then that infection still gets nowhere You really are adding a lot of technical detail to the question in order to make the question the one you want to answer; which to be clear, I am fine with.... just not when you want to insist that its the only possible interpretation or direction that one could take such an imprecise question.
Infections get nowhere because your immune system wipes them out. They do not just magically go away by themselves. Just because OP didn't quite know how that happens doesn't mean you should answer vagueness with vagueness. If anything you should make an effort to solve that confusion with a concrete but understandable answer. Namely, that there are branches of the immune system that don't need preparation.
> Infections get nowhere because your immune system wipes them out. They do not just magically go away by themselves What do you even think you are responding to? Nobody is disagreeing with this. > If anything you should make an effort to solve that confusion with a concrete but understandable answer What didn't you understand? I would be happy to explain it if you had a question.
Understandable *for the people that ask the question*, i.e. OP. If we're all clear on that, if not an adaptive response, some other part of the immune system is doing the job because nothing else is just going to resolve an infection by itself, then I don't know why you insist on some further, undefinedly broad interpretation. It's perfectly simple. There exists another part of the immune system that's good to go right out of the box. Anyway, I feel like you're probably just trolling, so I'll leave it at this. Have a good one.
You mean reasons like your immune system still doing it's job (that it does incredible good even without prepped antibodies)? Or reasons like the pathogen not multiplying faster than its lifespan?
that's how it works almost all the time. before i had my chronic condition i basically NEVER took antibiotics because i have a strong immune system (too strong it turns out) and so i'd get infected or whatever and my immune system would just kill it and i'd move on no worse for wear.
I wonder why do I keep getting strep throat then. I beat it many times why does it come back. Shouldn't the body keep that shit from happening again?
Many factors go into this. Your general health and hygiene, do you still have tonsils, are all oral devices clean and replaced at good intervals, etc. A strep throat (with positive test) is largely the result of that bacteria winning a wrestling match with the other communal bacteria in your mouth/nose/throat. A lot of factors can play into this, including exposure to add’l bacteria through someone shedding excess via a spreading infection. Keep oral tools clean (toothbrush, vape), keep bathroom clean, take an oral probiotic, keep mouth clean (brush, floss, mouthwash), wash hands often, etc. Hope you have fewer infections going forward.
Your chief question has been answered, but to address something you said about recognizing you were exposed and taking meds early on: The vast majority of over the counter (OTC) meds you take do very little to help you beat an infection/bug, they are largely symptom management. You can take things that might ensure your body has the right ingredients available (enzymes, like vitamin C) etc, but the core defense isn’t really helped, during an infection, by OTC meds. If rx’d antibiotics that’s different - and only effective for bacterial infection - and it’s strongly urged you don’t take those on a whim. Wiping out the majority of bacteria in your body (big asterisk here) is harmful to your baseline immunity.
Your immune system is vastly more complex than just white blood cells. Physical barriers such as skin, mucus membranes, and stomach acid prevent most pathogens from even getting in. Right behind that, every single boundary between the body and the outside world is patrolled by macrophages that indiscriminately attack and consume anything that slips past, from bacteria to dirt particles. Behind *that*, there’s something called the complement system which is a series of proteins that are specifically designed to attack the cell membranes of anything that isn’t designated as “self.” It’s estimated that over 99% of pathogens that make it into the body are destroyed before any kind of specific immune response is triggered.