Tag: Guinea Pigs

The First Successful Anti-Cancer Vaccine

Has the world already seen the first successful anti-cancer vaccine? Probably, and all thanks to animal research.

The Daily Telegraph ran an interesting article on a luncheon to honor Prof. Baruch Lumberg. Lumberg was instrumental in the creation of a vaccine to fight Hepatitis B. In fact, Lumberg won the 1976 Nobel Prize for medicine and has recently written a book, Hepatitis B: The Hunt for a Killer Virus, about his efforts to find a vaccine for the disease.

But the Hepatitis B vaccine should be — and apparently is — an anti-cancer vaccine as well. Hepatitis B plays a major role in causing liver cancer. As many as 85 percent of liver cancer cases are believed to be caused by the virus.

So widespread use of the Hepatitis B vaccine should result in declining liver cancer incidence. And in places where Hepatitis B was a major problem, that in fact has happened. In Taiwan, for example, the incidence of liver cancer has declined by half since the introduction of the Hepatitis B vaccine.

Lumberg first isolated the Hepatitis B virus in 1967 with epidemiological studies in human beings, but it was animal research that relied largely on guinea pigs and non-human primates that led to the development and approval of a vaccine for the disease in the early 1980s.

Source:

The world’s first cancer vaccine. Roger Highfield, The Daily Telegraph (London), June 26, 2002.

A Better Tuberculosis Vaccine?

The World Health Organization recently released a report on the daunting numbers of tuberculosis infections. It wasn’t too long ago that scientists thought that tuberculosis was on the verge of being wiped out, but complacence about the disease as well the HIV/AIDS epidemic led to a resurgence of the disease. According to WHO regional director in Southeast Asia, Uton Muchtar Rafei, “an estimated 40 percent of the population is infected with TB in our region and more than 1.5 million people died of TB last year.”

Worldwide, tuberculosis is the second leading cause of death from a single infectious agent.

When TB was last a major epidemic, at the turn of the century, a tuberculosis vaccine was created and refined from 1906-1919. The only problem was that it was only about 50 percent effective. Now researchers at the University of California-Los Angeles believe they may have created a much more effective vaccine.

Dr. Marcus Horwitz at UCLA led a study of the new vaccine that involved taking samples of the old vaccine and genetically modifying it to add a protein that is secreted from the organism that causes tuberculosis. “Most proteins of a bacteria are inside,” Horwitz told Reuters, “but there are some proteins which are actually excreted.”

Researchers then infected guinea pigs with tuberculosis, injecting half of them with the new vaccine and leaving the others unvaccinated as a control group. “The difference between the unvaccinated guinea pigs and those that were vaccinated is just day and night,” Horwitz said. “The unvaccinated animals, their lungs just became completely covered with tubercules and destroyed and the animals with the vaccine have one or two lesions which are contained.”

Testing should begin within a year to see if the vaccine is effective in human beings. If so, Horwitz said it should be able to be produced for just pennies a dose. The only drawback is that the vaccine won’t help people with AIDS since the vaccine could potentially disease itself in people with compromised immune systems.

Sources:

WHO finds TB, malaria return in killer diseases. Reuters, November 27, 2000.

Vaccine may work against tuberculosis. Reuters, November 30, 2000.

New skin test to reduce animal use

A recently formed interagency governmental
committee approved a new skin test for irritating chemicals that will
reduce, but not eliminate, the number of animals used for such testing.

The new test checks products to
see if they cause contact dermatitis. Currently contact dermatitis tests
use guinea pigs and cost American industry up to $1 billion annually to
perform. The new test uses mice and requires only one-third to one-half
as many animals.

The test also reduces the level
of animal suffering. In the old test, chemicals were repeatedly applied
to guinea pigs several times and researchers would then wait for the animals
to develop skin irritations. The new mice protocol calls for the
application of the chemicals, but after 6 days the mice are killed and
their lymph nodes examined for antibodies indicative of contact dermatitis.

William Stokes of the National
Institute of Environmental Health Sciences and chair of the interagency
committee that gave its approval and passed the test on to the FDA for
formal approval, said the new test combines the best of both worlds.

We think it’s a win-win situation. These new methods typically use
fewer animals, no animals or cause less pain and distress … but they
also incorporate new science and technology to provide more accurate
tests that do a better job of protecting public health.

In an odd move, even People for the Ethical Treatment of Animals endorsed the new test.

“We support any new test,”
said Mary Beth Sweetland, PETA’s director of research, investigation and
rescue. “Everything is relative – using a mouse lymph node beats
blinding an animal for months. A skin sensitivity test can last for any
number of hours, weeks or months.”

Source:

“U.S. scientists endorse more human lab tests,” Maggie Fox, Reuters,
Sept. 21, 1998.