Confusion Clears: Vaccines and how they work

Vaccines and how they work, generally but particularly as related to CL

This is a guest post from Bob Glass,Pan American Vet Labs
Hutto, TX
www.pavlab.com

I have posted on this before but this is a clear and easy to understand explanations. It is hard for me to achieve this, being trained in biology. I want to go into biochemistry and cell biology. This is called this and that is called that.

So I hope you understand this. If not, please comment here and I'll try to help. Or I'm sure Dr. Glass wouldn't mind you emailing him directly. This is his stock and trade.

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For the sake of simplicity I will use the term "vaccine" as a generic term
here. Actually the term vaccine is correctly used to described a
preparation which stimulates a protective immune response against a virus.
The term for the same type of product against bacteria is "bacterin" and
against toxins is "toxoid"

Vaccines are intended to "simulate" an actually infection in order to induce
the animal's immune system to react as if infected. In many (not all) cases
this will provide protection against future infections. This is the same
logic and mechanism which is employed with human vaccines.

If the same strain of a disease which causes disease were used, the vaccine
caused disease would be just as harmful as any "wild/natural" infection.
There are two strategies to overcome this problem. In some cases the
"vaccine" consists of a live but attenuated (greatly weakened) organism
which is not able to set up a persistent or disease causing infection.
Although weaker and less harmful than a natural infection this "vaccine"
infection will induce a protective immune response. A good example of this
is type of vaccine is sore mouth.

In other cases a killed vaccine is used. In this case the organism which
causes the disease is killed during the vaccine manufacturing process so
that no actual infection occurs. However the vaccine contains a large
number of these killed organisms which are able to stimulate the patient's
immune system. Often when a killed vaccine is used multiple doses are
required to sufficiently stimulate the patient's immune system. In both
these cases the goal of the vaccine is to stimulate an immune response that
kills the organism causing the infection.

In other cases a purified or semi purified vaccines is produced. A good
example of this is vaccines against toxins. Toxins are protein/carbohydrate
molecules produced by various organisms which have a pathologic effect on
the patient. Botulism is an organism which produces toxin. In these cases
it is not enough to kill the organism because the toxin will still be
present and cause life threatening illness. To combat this the toxins are
purified from the organism and "denatured" by various means
(heat/ph/chemicals) to make the toxin non harmful. This denatured toxin is
then injected into the patient who develops an immune response which
neutralizes the toxin. The antibody produced in the scenario is a
"anti-toxin". This is the same as the anti toxin you can buy and give to
animals that have not been vaccinated and become ill due to a toxin
producing bacteria. Anti Toxins are purified and concentrated antibodies
made by vaccinating animals with toxoids.

I have not read the article by Dr. Sparks, but I expect he referred to
introducing the disease organism into the goat (not the disease). In the
case of CL the organism is killed so the actual disease will not occur. In
some cases the patient may have a local immune response at the injection
site. In fact this is the body responding to the dead CL organism as if they
were "alive, thus the abscess, but in this case the CL is dead and the
abscess is "sterile".

I hope this helps;

Bob Glass
Pan American Vet Labs
Hutto, TX