Here’s an article from a few years ago about a cancer vaccine:
It says
It “attacks the mechanism by which it does harm.” But does it do so by getting the immune system to attack that mechanism? If not, I’m confused about what a vaccine is exactly.
I think they are misusing the term. Probably should be called an inoculation. The word itself comes from the Latin word for cow (something like vacca, I believe) and the original vaccination was intentionally infecting yourself with cowpox. That is a usually very mild version of smallpox and protects against smallpox. It was observed that diary maids rarely got smallpox. Over the years it has come to me any prophylactic inoculation, either with a tamed or killed version of the disease it was protecting against. The Salk vaccine against polio used killed virus; now they use weakened strains. The usage you quote is yet another extension of the term since the inoculation is not (I assume) a weak or dead version of the disease, which is not infectious in any case.
There are vaccines, which you are given when you are well. They make you immune so that you don’t ever get certain diseases.
Then there are treatments, which you take after you have caught a disease. They reduce the effect of the disease, maybe even make it go away.
They are saying that it’s a treatment, not a preventative vaccine. It won’t stop you getting cancer, but it will help your body to fight a cancer you already have.
This was mentioned (by WhyNot IIRC) in another recent thread about vaccinations. Also that “inoculation” is derived from in oculus, “in the eye” :eek:
It’s a vaccine in the sense that it is an injection of an antigen that stimulates your immune system to produce more antibodies that attack the antigen. In this case, the antigen is a growth factor (EGF) that causes some cancer cells to divide.
Just from the few summaries I glanced over, I’m puzzled by how it works. The immune system normally eliminates cells that make antibodies that can bind to proteins made by your own cells. How does this vaccine overcome the negative selection against self recognition? Then, if it works as advertised, what are the side effects of causing an autoimmune reaction against a growth factor with lots of normal functions in a healthy body?
There is a Rabies Vaccine, but the post exposure treatment to someone who hasn’t been vaccinated seems to be more of the Vaccine.
How can this work? Surely the Rabies virus is doing a good job jiggig up your immune system already?
As an aside, we know that when the major Rabies symptoms appear death is essentially certain. However, how many people get infected and don’t progress to the major symptoms and survive - perhaps unnoticed?
Antibodies do not “attack” hostile microbes, they are not even very complex things (not alive in the same sense as the lymphocytes that do the work).
Any given cell has a number of different structures embedded in its membrane, primarily for moving desirable stuff into the cell and expelling waste products and metabolic byproducts. These membrane structures may be of a unique configuration or arrangement that may make it possible for the immune system to see them and figure out what sort of cell it is looking at.
Once a hostile agent is identified, the immune system starts making lots of tiny antibodies that are shaped to fit certain membrane structures and bind to them. Lymophyctes notice antibodies bound to target cells and go swallow those cells up.
So, if antibodies can be produced that match specific unique membrane structures in cancer cells, they would, in theory, bind to those cancer cells and signal the lymphocytes to come have lunch here (lymphocytes are rather mobile, they can move out of the bloodstream and wriggle through tissue).
It sounds like a good theory – if the cancer cells carry unique membrane structures that can readily be bound by antibodies.
The rabies virus is a bit unusual in that it hides out exclusively inside nerve cells. Normally the immune system doesn’t really “patrol” those cells. The vaccine, however, stimulates a population of cells that react to the rabies antigens, and once those are around, they “notice” the infected nerve cells and do their job.
It also has an incubation period of weeks to months; the vaccine works it if is administered as soon as the bite occurs.
The ‘oculus’ part of ‘inoculation’ just comes from the practice of the piece being transplanted referred to as the ‘eye’ in plants.
Another blanket term is ‘immunization’.