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Antibiotics.
Antivirals.
Vaccines.
Have you ever wondered what they do or how they work?
One thing to understand is that they can greatly help the work of your immune system.
Your immune system is fascinating.
We’re being very general here because this is not a video about the immune system specifically,
but it’s important to understand a few basics of the immune system to comprehend the amazing
work of antibiotics, antivirals, and vaccines.
Your immune system is designed to protect you against pathogens.
Pathogens can be all kinds of things.
Certain kinds of bacteria.
Viruses.
Infectious protists, yes, unfortunately there are some dangerous types of protists.
Certain types of fungi.
Parasitic worms.
These can all be pathogens.
Your skin is actually part of your first line of defense in protecting invasion of pathogens.
Not just as a barrier, but also, there are helpful microbes that colonize your skin and
can keep bad microbe numbers down.
Mucous membranes are also part of the first line of defense.
But pathogens do get in, and when they do, you have more lines of defense to protect
you.
For example, your second line of defense includes non-specific white blood cells such as macrophages.
These cells are incredible; they actually engulf pathogens.
These are involved in a fascinating response called the inflammatory response which we
could have an entire video on.
Then, you have a third line of defense.
Unlike the first two lines of defense, the third line of defense is considered more of
a specific defense as it can target specific pathogens.
Examples of immune cells involved in this specific response include white blood cells
known as lymphocytes.
T lymphocytes, or T cells, and B lymphocytes, or B cells.
B and T cells are very specific for reacting to antigens.
Antigens are molecules that can be found on the pathogens.
Although we should point out that antigens can be anything foreign in your body ---for
example, someone who has an allergy to pollen may react to pollen antigens.
An antigen can activate a response from a T cell and/or a B cell.
And, while again, this video doesn’t get into the fascinating types of immune responses
with these cells which we encourage you to explore, we do want to mention one very important
fact before we move on.
There are memory B and T cells.
This is very significant because these cells can “remember” a pathogen.
These memory B and T cells remain in the body.
If the pathogen returns, these cells can multiply and combat the pathogen quickly and effectively.
We’ll explain why that’s especially important when we get to vaccines.
So back to antibiotics, antivirals, and vaccines.
How are they involved with all of this…what do they do…how do they work?
Let’s start with antibiotics.
Antibiotics target one type of pathogen: bacteria.
Now while not all bacteria are bad---in fact, many bacteria play many helpful roles in both
our bodies and the environment---the infectious types of bacteria can be a problem.
It is bacteria that cause strep throat, staph infections, some types of pneumonia, UTIs.
And while your immune system will go after these bacteria, sometimes it could use a little
help.
That’s where antibiotics come in.
Antibiotics can destroy bacteria in many ways…they can damage bacterial cell walls or block the
production of critical proteins the bacteria may need.
Antibiotics can be prescribed by a doctor in a pill form, but they can also be injected
or delivered in an IV.
Now the word antibiotic can be taken apart where you see “anti” which can mean against
and “bio” which can mean life.
And that’s really helpful because you don’t want to get it mixed up with two other words
that, unfortunately, sound quite similar.
One of those words is antigen, as we had mentioned earlier, which is a molecule that can be found
on a pathogen.
Antibodies are proteins made by some of your immune cells, such as B cells, that can be
used to help fight pathogens.
They often have this fascinating Y like shape.
Some antibodies bind to a pathogen making the pathogen unable to function correctly.
But antibodies also can be used to mark pathogens so they can get “eaten” by a macrophage.
Now, we had mentioned that immune cells can contain a type of memory when they encounter
a pathogen.
This can include the ability to produce antibodies against pathogens that your immune cells have
already encountered.
And this is where vaccines come in.
Vaccines are a way of exposing your body to an inactive form of a pathogen or a weakened
form of a pathogen---since it’s inactive or weakened, it prevents you from actually
developing the disease from the vaccination itself.
However, your body still launches an immune response.
By launching an immune response, which includes the production of antibodies against the pathogen,
the immune system will retain “memory” against the pathogen.
That way if your body ever encounters the real, active pathogen---your body will be
familiar with it already and therefore we say that your body already has immunity against
the pathogen.
This can result in allowing your body to launch an attack against the real thing more quickly
and efficiently.
Vaccines can be effective against many different types of bacteria and viruses.
We take for granted the amazing work of vaccines in keeping people from developing devastating
bacterial and viral diseases.
But thanks to vaccines, some horrible bacterial and viral diseases are considered eradicated
in some areas, but it is important for them to be continued to prevent some of these diseases
from re-emerging.
There’s also another really important thing you should know about vaccines.
Some people may not be able to receive certain vaccinations---from someone whose immune system
is severely compromised because they perhaps have an illness of some type---to a newborn
baby not yet old enough to receive many vaccines---to a pregnant mother.
These vulnerable populations rely on something known as “herd immunity” - that is, if
others around them are vaccinated against a certain pathogen, that may offer them a
degree of protection against that pathogen because it cannot easily spread to them.
So vaccinations not only offer protection for the person receiving them, but also, they
can offer protection for others around them.
For an example of this, let’s consider the contagious viral disease Rubella.
A vaccine for Rubella is given typically in early childhood.
Rubella generally results in a rash with some mild symptoms such as a low grade fever or
sore throat.
But, if a pregnant woman contracts this virus, her unborn child can suffer severe birth defects.
But women who are pregnant are advised not to get the Rubella vaccine while they’re pregnant
so they can be considered a vulnerable population during that timeframe if they do not already
have immunity from this virus.
Herd immunity can be protective in an example such as this.
Learn more about “herd immunity” in some of our further reading suggestions.
And, because there is a lot of misinformation about vaccines out there especially as of
recent years, we have also included some further reading suggestions about vaccines in general
that you may want to check out.
So as we discussed, vaccines can help our immune system be ready for all kinds of pathogens,
including bacteria and viruses.
Recall that antibiotics are specific against bacteria only.
But antivirals are designed to help target viruses.
Antivirals can come in many forms such as a pill, liquid, or given as an IV form.
They can make a virus infection less severe, although many of them have to be given in
a specific time frame after contracting the virus in order to be effective.
Many antivirals work by affecting virus replication, which is difficult, because if you recall
from our virus video, viruses reproduce by using your own cell’s machinery.
So an antiviral needs to be able to stop the virus without negatively affecting your own
cells.
For example, if the virus has a critical protein that it uses the host cell to make---an antiviral
can be designed to stop that protein from being made---but it would be important to
verify that the protein is not one that is used by your own cells.
One last thing.
Pathogens can change.
Mutate.
Evolve.
In our natural selection video, we talk about how antibiotics may not be as effective against
certain types of bacteria due to antibiotic resistance that can occur.
In our virus video, we mention how viruses can mutate.
An example is the virus that causes influenza, aka the flu.
That virus changes frequently so a flu shot vaccine that works this year likely won’t
be as effective against the influenza virus that is the most common next year.
There are actually scientists that work hard to predict which influenza virus type will
be the most common each year, and the flu vaccine is designed to launch an immune response
against that specific type so that, if you encounter it, you can have protection.
That’s why there is a different flu shot each year and sometimes the effectiveness
can vary each year.
With mutations occurring, this is also a challenge in developing antivirals.
An antiviral that was designed to target a specific virus may not work on a mutated form.
Scientists continue to look for solutions to counter the ever-changing pathogen world.
Well that’s it for the Amoeba Sisters, and we remind you to stay curious.