 All of life has proteins, so human cells have proteins. And the same is true for viruses, even though they're not cells, like we think of technically, right? They have proteins. Virus is kind of made up of kind of two main things. One is a protein shell and then genetic material. So this is a 3D printed model I made of proteins from the human papilloma virus. And these proteins form together. Each one of these kind of colored pieces is made up of five different proteins and you put a bunch of them together, you make this kind of icosidihedral shell. And then inside, I've represented the genetic material here as a red strand. And that's basically essentially what a virus is, its structure is made up of. So in this case, we can see, right, the protein is making its function is to make a shell, a protective shell around it. Some viruses also have a plasma membrane or a lipid membrane around them. I haven't quite figured out how to model it yet. Maybe a plastic bag or something. Like I mentioned, the spike protein has two main roles for the virus. One is to recognize and bind to human cells. And so the top part of it is gonna recognize another protein that's on the cell surface. So if imagine my arm is the cell surface, it's gonna connect to a protein there. And the protein that it recognizes in human cells is called ACE2. Once it recognizes that ACE2 protein, there's a more kind of complicated process in which the spike protein actually unfolds and it's like a long thin structure and allows it to kind of stick into the plasma membrane and basically fuse the plasma membrane of the virus with the plasma membrane of the cell. It all has to do with the shapes and particularities of the spike protein and ACE protein. And I don't know if you can see, but right the surface is all really bumpy and each of those little kind of little bumps represents individual atom. And the structure of the spike protein is specific and that the surface here is gonna recognize the ACE2 protein. Sort of like a puzzle, a puzzle piece that fits just right where people kind of use the analogy of a lock in the key. And all comes down to the shape of the proteins and also some with charge. So some amino acids have a positive charge, some have a negative charge. So you can imagine each of these dots might be kind of like a little magnet so that connection of finding the right shape and connection is also kind of dependent on surface charge. Yeah, so this is where it's kind of cool is that these are mRNA based viruses and I guess we shouldn't say what mRNA is. mRNA is genetic material that's going to encode for protein, has instructions or information to make that protein. So in the simplest case, we are using this red pipeline to represent the genetic material inside a virus. And so for the spike protein, there's a mRNA that carries instructions how to make that protein chain, our kind of green chain of amino acids, put all these little beads in the correct order. So with these vaccines, they take the mRNA sequence for the spike protein and they put in a special package and deliver that inside to your human cell. And once it's in the cell, your body is going to make that protein. Some of that protein is going to end up on the surface of your cell and then that's where the immune system kind of takes action. This is a foreign protein we're going to try to seek out and destroy that protein. The mechanism, how do we get that mRNA into the cell? In some ways it's kind of like the way the virus is to it. With the vaccine, it's encapsulating this kind of lipid droplet. And right, you can think of this, it's sort of like a plasma membrane and in some ways it's very much like our virus, right? It's just a simple package with genetic material inside. And then the role of the virus is to get that genetic material inside. So let's talk about antibodies, right? Antibodies are another kind of protein, so I've got another 3D printed model. Antibodies are protein that kind of take a Y-like shape and their job is to recognize things in your body that are foreign like bacteria and viruses and how they do that. Well, basically the shape at the tips of the Ys here is slightly different from antibody to antibody. So your body makes somewhere around like a billion different antibodies and mostly they differ here at the tips. And this tip here is what's gonna recognize the foreign particles in your body. So as an example, right? We've got the SARS-CoV-2 spike protein. So there's hopefully an antibody floating around in your body that's gonna recognize the surface of that spike protein, right? And the specific shape of the little nooks and crannies and the charge of that antibody has to match just right to the shape and positive negative charge on the surface of the spike spike protein, right? Once it recognizes, it can have a direct role in that now it kind of blocks that virus protein. So remember this virus protein is trying to find your ACE protein, right? So now if you've got an antibody stuck on there I can't do that anymore, right? And so this is this process of what we call the neutralizing antibody, right? So it stops it from attaching the cell. The other thing it can do is once it's kind of attached, it acts as sort of like a flag and then your cell can recognize that flag and says, okay, go eat this thing. This is a thing that's bad for your body. So it kind of has two main roles. It all has to do kind of with floating around and bumping into each other, which is maybe a little concerning that the fate of our health, right? Depends on these molecules floating around and finding each other. But you've got a lot of antibodies and if you're infected with a lot of viruses but they'll float around and if they meet the right, just the right surface and bump the right way then they'll attach to one another.