The Immune System: Your Own Personal Military

 To understand how vaccines and other pharmaceuticals work, we need to understand the immune system. You can think of your immune system like your own personal army protecting you from outside threats. With this in mind, the first term that we should define is pathogen: an agent that causes disease. These can be foreign bacteria, like Streptococcus pneumoniae, which causes pneumonia, or it could be a virus, like the Measles virus. Your immune system is designed to protect you from pathogens. Pathogens carry foreign proteins that are referred to as antigens and these antigens are what trigger your immune army to attack.

Figure 1: White blood cell types.

Figure 1: White blood cell types.

So who is involved in this very important immune army?  The immune cells are called lymphocytes (aka white blood cells) and are made up of T cells and B cells (Figure 1).  There is a difference between T cells and B cells in where they are produced and how they interact with antigens, but for simplicity, I am not going to delve into the differences. Both T cells and B cells work synergistically to create long term immunityI am going to focus my explanation on B cells. 

Figure 2: B cell function.

Figure 2: B cell function.

B cells produce and secrete little Y-shaped proteins that bind to antigens (Figure 2). These Y-shaped proteins are referred to as antibodies and are specific to a particular antigen. These antibodies then roam around your blood system and if they encounter the pathogen they are specific for, they will bind to the antigens on the virus or bacteria pathogen. This marks the pathogen for destruction. Large cells called macrophages will come along and eat the virus or bacteria cells marked with antibodies and destroy them.

Your Body at War: A Summary of Your Immune System

A foreign invader (a virus or bacteria) enters your body and makes you sick. Your immune system sends in its troops, the White Blood Cell corps, to fend off the invaders. The cells create and secrete proteins called antibodies that will mark the invaders. Then large cells called macrophages come along and eat the foreign cells that have been marked by the antibodies. After you’ve defeated the enemy, you keep the antibodies. The antibodies will then continue to patrol your body’s perimeter and if that particular invader tries to come back in, the antibodies will mark it for destruction before it can even cause disease.

How then does vaccination work?

The idea with vaccines is that you trick your immune system into thinking that it has the disease. You provide your immune system with the necessary antigens to create an immune response, but doesn’t provide it with the actual disease causing agent. Therefore you get an immune response but you don’t get sick. Your body will produce antibodies against that particular disease so that when you are exposed to the actual disease, your immune system immediately marks the pathogens and destroys them before they have a chance to make you sick.  

I said above that your immune system usually wins, so why do we even care about this? Well, just because your immune system may win, it doesn’t mean that it does not suffer some losses. For example: measles, you may not die, but you may end up losing your hearing. Mumps: you may actually lose your ability to reproduce. Polio: you may be paralysed for life. And of course, you can actually die. The flu causes over 100 000 deaths world wide every year, and that doesn’t even count the millions who have died in massive flu pandemics prior to the advent of the vaccine. 


The Truth About Vaccines

Here at Curiosity Science, we are big fans of vaccination. It is one of the simplest things that you can do to improve your health and it is the way that we will cure diseases. The fact that smallpx no longer threatens us is the best example of how vaccination cures and eradicates diseases. That is, afterall, the goal of modern medical research: to cure and eradicate diseases.  However, in recent years, vaccination has come under fire from an anti-vaccine movement.

The anti-vaccination movement is an example of a poor understanding of science mixed with fear mongering. As I said, we here at Curiosity Science are all about vaccines and vaccination. The science is sound. To quote Neil Degrasse Tyson: “The good thing about science is it is true whether or not you believe in it.”

Now, that being said, Curiosity Science is also a welcoming place to anyone who has vaccine concerns. One of my biggest concerns has been how frustrated us on the pro-vax side have become that we are almost jerks to anyone who questions vaccines or vaccine safety. I get that. Believe me I have been there-it is especially frustrating when you see otherwise intelligent people fall victim to erroneous internet fear articles that come from seemingly legit websites like This information is not cultivated by experts in the field; it is cultivated by a man who fears that vaccines are somehow to blame for his kid “not meeting the developmental milestones”.

Why is this a concern? Well because people are making jumps that are not proper conclusions by reading a list of ingredients in vaccines and thinking they are somehow nefarious. The problem being that most people don’t have enough chemistry to understand what those crazy “chemically sounding” ingredient names mean. That is why you want to talk to experts about those things. You wouldn’t take surgery advice from someone who isn’t a surgeon right?

This is why I want to emphasise that here at Curiosity Science we are friendly and open to all concerns about vaccines. If you want actual, scientifically verified information, please look here. If you want to talk to an immunologist or a pathobiologist or a pharmaceutical chemist, send us an email at It is ok to have questions and concerns. I also encourage all of you who are trying to change the minds of anti-vaxxers to do your best to create a friendly, open dialogue. Making people feel stupid (no matter how frustrated you get) is never going to be a winning strategy.

For those of you who are concerned about vaccines check out this awesome comic. There is no conspiracy; only a plea to make our population as healthy as possible! Vaccinate yourself against misinformation and know your experts.

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What’s in a Blood Type?

Have you ever wondered about your blood? What makes type A different from type B? Maybe you are a blood donor and are curious why your blood type is different than your parents or siblings?

What determines the blood type is proteins found on blood cells called antigens. The antigens that are most commonly used to type blood are called type A, type B, and the Rhesus factor. If you have the A antigens, then your are blood type A. If you have the B antigens, then you are blood type B. If you have both A and B antigens, then you are blood type AB. If you lack these antigens completely (i.e., you have neither A or B antigens) then you are blood type O. The Rhesus factor is classified as to whether you have that protein (positive) or you lack the Rhesus protein (negative). Putting this all together, someone with a A antigens and the Rhesus factor would therefore have blood type A+. Someone with ALL of these antigens, A, B, and Rh, would be blood type AB+ and someone who lacks all of these antigens would be blood type O-.

Now, these antigens don’t really make a difference to your health, anymore than the colour of your eyes or hair. They will, however, make a difference if you receive a blood product, say for a surgery or something. You can only receive blood that is compatible with your blood type. To be compatible, the blood you receive must not contain any antigens that you don’t already posses. This is because the presence of foreign proteins will cause an immune reaction, which produces immune proteins called antibodies. The blood type O- has no antigens and therefore can donate to ALL blood types. This blood type is called the universal donor and that is why it is in most demand. The blood type AB+ has all anitgens and therefore won’t raise an immune response to any of the blood types and is called the universal receiver. Canadian Blood Services has a wonderful explanation of the different blood types, who they can donate to and receive from on their website.

For me what makes blood types really interesting is when you start looking at blood components. Blood is largely made up of plasma, red blood cells, white blood cells, and platelets. Red blood cells transport oxygen to the body tissues; white blood cells are immune cells, platelets are cells that are used in clotting, and plasma is the liquid part, that contains the proteins and nutrients in the blood that are required by the tissues in the body. Plasma alone can be used to help individuals with bleeding disorders, liver diseases, and cancers. It can also be used in the production of vaccines or other pharmaceutical products, such as immune globulin used to treat tetanus infections. What is really cool about plasma is that the most in demand blood type for plasma donation is AB+. This is because it is the universal PLASMA donor.

blood donation 45 copy

This might be surprising since above I wrote it is the universal receiver. For whole blood (blood that contains all of the cells and plasma) it is the universal receiver. But once we remove the cells with the antigens leaving only the liquid plasma, it becomes the universal donor. Any antibodies that are present in the blood will be in the plasma, and we know that AB+ won’t form antibodies to any of the blood antigens because it has all three. This means that there will be no antibodies in the plasma that could cause a problem. What is a problem though is that AB+ is the second rarest blood type. Only 2.5% of the population has this blood type. (The rarest blood type is AB- with 0.5% of the population having this type.) I happen to be one of these people, which I have always thought was really cool. The picture on the right is me at my 45th blood donation with Canadian Blood Services.

If you can donate blood, whole or plasma, please do. Not only does it save lives, but it is pretty cool science.