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Yeast Vaccine (video)
July 25, 2001

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A vaccine effective against the AIDS virus has long been a goal of researchers, and now they may have one.

As this ScienCentral News video reports, the vaccine is made of simple yeast that can help fight the disease by kickstarting the immune system.

How do traditional vaccines work?

Thanks to vaccines, the threats of polio, smallpox, and rubella have been virtually eliminated from the population. A simple injection, sometimes repeated, is all it takes–but how do these medical marvels really work?

In the normal course of infection, a bacterium, virus, or other disease-causing nasty wiggles its way into the body and begins reproducing. In the body’s immune system, B-cells constantly patrol the tissues for suspicious characters, or "non-self" cells until they come across the infecting agent and sound chemical alarms in the form of antibodies. These act as not only a wake-up call to the immune system, but also provide identifying information about the germ, similar to a fingerprint.

The virus or bacterium is then on the run as the antibodies attach to it, marking each invader for death. The immune system’s cytotoxic cells, or "killer" cells, then move in on the marked pathogens and engulf them, dissolving them with enzymes and other chemicals.

All of this happens when you’re feeling healthy. When you get sick, you’re witnessing what happens when the immune system doesn’t catch the germ quickly enough. In the case of a minor cold, simple rest and fluids allow the immune system to make up for its earlier leniency and take care of the disease over time. In the case of more serious infections like polio, however, the disease may do considerable damage before the immune system has time to catch up.

A vaccine is where medicine meets nature halfway

Before a patient comes into contact with the deadlier viruses or bacteria, a vaccine’s job is to alert their healthy immune systems and give them the identifying information they need to sound a more comprehensive alarm, should they ever come in contact with the pathogen by normal human transmission.

Today, many diseases, once identified and thoroughly studied by scientists, can be weakened or killed in a lab, and the resulting inactivated form is introduced in healthy person, hopefully giving their immune system all the information it needs to destroy it on the next sighting.

But a vaccine is only as effective as the immune system it works with. If the immune system is somehow weakened by other factors (such as AIDS or malnutrition), the weakened form of the germ may be enough to start an infection. (This, however, is what makes the yeast vaccine so special—unlike germs, yeast is utterly harmless.)

So with the risk of introducing infection through vaccines, why can’t we simply inject people with the virus-killing chemicals the cytotoxic killer cells use? There is a simple reason: These chemicals kill normal body cells and germs equally well. With our immune systems at the wheel, though, the cytotoxic cells only eat that which has been "flagged" by antibodies. And occasionally errors do occur in the flagging, and the immune system attacks healthy body cells, giving rise to an autoimmune disorder like type 1 Diabetes or rheumatoid arthritis.

In non-immune-suppressed, healthy individuals the risks of infection from vaccines is quite slim. According to the CDC, "The risks of serious disease from not vaccinating are far greater than the risks of serious reaction to a vaccination."

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