Researchers Turn Mosquitoes Into Flying Vaccinators
Posted Apr 07 2010 6:41pm
Scientists have dreamed up various ways to tinker with insects’ DNA to fight disease. One option is to create strains of mosquitoes that are resistant to infections with parasites or viruses, or that are unable to pass the pathogens on to humans. These would somehow have to replace the natural, disease-bearing mosquitoes, which is a tall order. Another strategy closer to becoming reality is to release transgenic mosquitoes that, when they mate with wild-type counterparts, don’t produce viable offspring. That would shrink the population over time.
The new study relies on a very different mechanism: Use mosquitoes to become what the scientists call “flying vaccinators.” Normally, when mosquitoes bite, they inject a tiny drop of saliva that prevents the host’s blood from clotting. The Japanese group decided to add an antigen-a compound that triggers an immune response-to the mix of proteins in the insect’s saliva.
A group by led by molecular geneticist Shigeto Yoshida of Jichi Medical University in Tochigi, Japan, identified a region in the genome of Anopheles stephensi-a malaria mosquito-called a promoter that turns on genes only in the insects’ saliva. To this promoter they attached SP15, a candidate vaccine against leishmaniasis, a parasitic disease spread by sand flies that can cause skin sores and organ damage. Sure enough, the mosquitoes produced SP15 in their saliva, the team reports in the current issue of Insect Molecular Biology. And when the insects were allowed to feast on mice, the mice developed antibodies against SP15.
Antibody levels weren’t very high, and the team has yet to test whether they protect the rodents against the disease. (Only very few labs have the facilities for so-called challenge studies with that disease, says Yoshida.) In the experiment, mice were bitten some 1500 times on average; that may seem very high, but studies show that in places where malaria is rampant, people get bitten more than 100 times a night, Yoshida points out. In the meantime, the group has also made mosquitoes produce a candidate malaria vaccine.
Other researchers are wowed by the achievement. “The science is really beautiful,” says Jesus Valenzuela of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who developed the SP15 vaccine. David O’Brochta, an insect molecular geneticist at the University of Maryland, College Park, calls it “a fascinating proof of concept.”
So why won’t it fly? There’s a huge variation in the number of mosquito bites one person received compared with the next, so people exposed to the transgenic mosquitoes would get vastly different doses of the vaccine; it would be a bit like giving some people one measles jab and others 500 of them. No regulatory agency would sign off on that, says molecular biologist Robert Sinden of Imperial College London. Releasing the mosquitoes would also mean vaccinating people without their informed consent, an ethical no-no. Yoshida concedes that the mosquito would be “unacceptable” as a human vaccine-delivery mechanism.
However, flying vaccinators-or “flying syringes” as some have dubbed them -may have potential in fighting animal disease, says O’Brochta. Animals don’t need to give their consent, and the variable dosage would be less of a concern.
Dr. David Ayoub is a specialist on components used in vaccines. Thimerosal isn’t the only thing to worry about he says: use of aluminum may prove to be even more toxic than thimerosal was.
Ayoub became interested in the use of aluminum in vaccines and its effects after hearing about the high levels of aluminum found in autistic children and those with ADHD. A nutritionist showed Dr. Ayoub toxicity studies in a school in which 90% of the children developed ADHD in a single year. Their toxicity profiles showed massive amounts of aluminum.
Aluminum is used as an adjuvant in vaccines: it boosts your immune response to the antigen, the infecting agent. Scientists are still unclear about how adjuvants work but they use them so that they can use fewer antigens and cut costs.
Dr. Ayoub discovered that the FDA guidelines of aluminum content in vaccines was based on its effectiveness as an adjuvant and does not take safety into account.
Aluminum is used in hepatitis vaccines, diphtheria, tetanus and pertussis vaccines, Hib vaccines, Gardasil and pneumonia vaccines.
One of the highest concentrations of aluminum is found in Pediatrix, says Dr. Ayoub. This combination vaccine given to children contains 450 mcg more aluminum than what’s normally used in vaccines. Children also get multiple vaccines at once, compounding the problem. According to Dr. Ayoub, children today receive 13 more aluminum-containing vaccine injections than kids did in the 70’s and 80’s and the dosage in each has more than doubled.
Blaylock bemoans the fact that today, children receive 23 or more vaccinations before the age of 2 and 36 or more by the time they enter school and that the CDC urges parents to get their child a flu shot every year. The majority of flu shots in the US still contain a full dose of Thimerosal, says Blaylock.
He points out that CDC and other agencies often reassure people about the safety of vaccinations even though the same agencies once claimed that cigarette smoking didn’t cause lung cancer, mercury was not only safe but it raised IQ, and that Thimerosal was safe even though no study had been conducted on its safety.
Both aluminum and mercury accumulate in the brain—not the blood, says Blaylock, so blood tests of mercury levels don’t mean much when they’re done by vaccine manufacturers. Mercury found in the brain has a half-life of 20 years.
Aluminum is toxic and impairs the body’s ability to rid itself of mercury. It also impairs glutathione synthesis, the compound that detoxifies the body and aids vital biological processes.
Vaccines & Immune Response
Without going into too much detail, our bodies have a TH1 immune response and a TH2 immune response. Vaccines stimulate the TH2 response in the body. This is more like an “emergency immune response.”
By having an immune system that is trained to respond with a TH2 response (which is inflammatory in nature), you then weaken your TH1 response (which is responsible for fighting viruses, parasites and cancer cells).
So in essence, it’s like we are trading childhood diseases like chicken pox for cancer and autoimmune diseases.
Retired neurosurgeon Russell Blaylock has reviewed the research on autism and vaccinations. He says that the most compelling work has found that repeatedly stimulating the immune system primes immune cells in the central nervous system. Subsequent vaccinations then cause intense reaction in these cells and inflammatory responses in the central nervous system. This affects the development of neuronal pathways in a growing child’s brain and can even lead to degeneration of existing brain structure.
Blaylock, and scientists who followed, have found that brain inflammation and immune cell reactivity exist in autistic people of all ages and that immune-stimulating substances such as the aluminum and mercury used in vaccines can promote these occurrences.
When we get an infection naturally, he says, our immune system quickly shuts down after the threat is taken care of to minimize damage to healthy tissue. When vaccinations are used, the immune reaction doesn’t shut down. That high-pitched crying from infants after vaccinations? Blaylock calls it the “encephaltitic cry:” it’s due to brain inflammation.