Vaccines have been around for over a century. Some even more in a rudimentary form. Let us take a brief look.
First we have antigen presenting cells, cells that wander around looking for "stuff" that does not belong, like viruses.
They have proteins on their surface that work one of two ways. We focus on those with MHC II proteins.
Now as these APCs move about they collect proteins which we call antigens. They take these Ag and present them to the immune cells.
The T cell is one such immune cell and one which does a great deal to koll off the invader. Thus we need to get that T cell, a cytotoxic T lymphocyte, CTL activated against the Ag, and thus against the invader.
A second path is the B cells and the generation of antibodies, Ab. Ab are generated by the B cells and they go out and cover invading cells as markers.
The overall process is shown below in simple form.
We can summarize this as below.
Now there are multiple ways to generate a vaccine to kill off the invader. The classic manner is shown below. We use inactivated or weakened viruses and hope they stay that way. We inject them and then wait for an immune response. This is done by generating live virus elements oftentimes in eggs. This is a long and costly process, needless to say, using a lot of eggs.
A second way is a DNA vector injected into a patients and we use an electric shock to open the cell surface.
We can also use RNA to generate the Ag via a normal vaccination. Both of these are highly scalable and no eggs required.
A third way is a protein vector such as the COVID protein but with segments deleted.
Finally is a viral vector where we use the deactivated protein but place it in a more benign virus.
Just which of these will win out is unknown.
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