Geek Out: A Vaccine Post That Doesn’t Talk About COVID?

Our immune system works

Full disclosure, we’re really aiming to provide just an overview here. The immune system comprises: organs (tonsils, spleen and a whole lot of others too), vessels (that lymphatic circulation that we hear about from masseurs and unfortunately, cancer specialists), cells (probably dozens of different types) and chemicals (antibodies and a gazillion other, less well-known).

Our immune system is mysterious and complex which is illustrated by the fact that more than 10% of all the Physiology/medicine Nobel prizes have been awarded for breakthroughs in understanding how we fight off germs.   

Pathogens:

This word was created by smooshing pathology (disease) and generation together to create pathogen, a “something” that causes disease.

Innate immunity:

Actually way more than skin and vomiting! Tears, acid in our stomach, mucus in our airways, fever, these are just a few examples of innate immune system processes.

Never forgotten:

At this point, some of you may be thinking “never forgotten? How do I get a cold 4 times a year or regular strep throat infections then?”.  The answer is it’s not the same cold virus or the same streptococcus bacterium that’s infecting you.  On the other hand, if you have a stinky cold, recover but give it to your partner who then proceeds to cough all over you, then you don’t have to worry.  You won’t catch the same cold back, your immune system will remember it!

Identify:

This isn’t going to be a surprise I’m sure but there’s quite a bit to this identification of pathogens by B lymphocytes.

Every one of our trillions of B lymphocytes carries molecules all over the ir surface called B cell receptors (BCR). Every one of our B lymphocytes has differently shaped BCRs from the trillion other B lymphocytes but each B lymphocyte is covered in probably millions of the same BCR.

Think of these BCRs as jigsaw puzzle pieces.

Okay, so not actually jigsaw puzzle pieces but molecules that have a particular, almost unique shape and the puzzle pieces on our B lymphocytes test out everything they come in contact with, looking for the matching, interlocking puzzle piece.

Pathogens are covered in tiny jigsaw puzzle pieces too.

Again not really, but close enough.

When a B lymphocyte encounters a pathogen carrying a matching puzzle piece, the B lymphocyte and the pathogen interlock, completing the world’s simplest, 2 piece jigsaw - the pathogen has been identified/recognized!

And finally on this topic, we’re not using “antigen” in this conversation but heard that term before and curious?

The word antigen is a portmanteau of antibody and generate – antigens are anything that poke the immune system into producing antibodies.  Sometime the whole pathogen is an antigen, more often though, it’s quite a small something on the surface of the bacterial or parasitic cell, fungal spore or virus particle that’s enough for our immune system to go “stop right there, I don’t recognize you” and to start the process of developing immunity, including the production of antibodies.

Only one/Antibodies are super specific:

For example, about 30% of all colds are caused by a Coronavirus and we recover once a B lymphocyte encounters that virus, makes lots of plasma cells that produce identical antibodies which target that cold-causing Corona virus.

Those antibodies won’t recognize a sibling corona virus responsible for next year’s common cold and they definitely can’t recognize the more different, cousin corona virus responsible for COVID-19. Shame, because if they did, we wouldn’t have had a global pandemic as enough of us would already be protected because of our, on average, 4 colds every year!!

Phagocytes:

comes from two Greek words, phage, to eat and cyte, cell so literally “eater cells”, I love that!

 Killed:

Full disclosure, it’s not correct to refer to vaccines being killed because they were never alive! Viruses are classed obligate parasites as they are obligated to behave as a parasite! A vaccine is just a piece of genetic code and without entering a cell and the cell copying that viral code, nothing happens. So a virus can’t be killed but bacteria, fungal cells etc absolutely can be!