Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Greetings everyone and welcome to yet another excursion through the headlines of science. You don’t see this stuff much of anywhere else but here, which is sad. It implies that there isn’t much interest in science but of course, Americans are notorious about their news preferences. The Australian government is currently undergoing a crisis and we get news about bedbugs in the Empire State Building. Although that’s something I would write about, I’m not sure it’s worthy of major headline news.
Today we’re going to take a little excursion into what ails us, and the news for the most part is good. The most dangerous animal on the face of the planet, the one that kills the most humans every single year is sitting somewhere in your back yard right now. Strangely enough, you’re not afraid of it like you are the shark and the grizzly bear and the crocodile. What is this dreadful killer? The mosquito! But there’s good news on the malaria front.
VACCINATION FOR A KILLER
The real problem about malaria which sickens almost a quarter of a billion people each year and kills a child every 30 seconds is that there is no vaccine to prevent the mosquito from infecting you with it. That may soon change. Researchers at Rockefeller University have genetically transformed the yellow fever vaccine to prime the immune system to fend off the mosquito borne parasites that cause the disease. They’ve discovered that the modified vaccine, along with a booster, provided mice with immunity to the deadly disease.
Malaria is one of the most pressing health crises of developing countries: in communities stricken by infection, attendance at work and school drops, and poverty deepens. It’s been known since the ‘60’s that one form of the malaria parasite — called the sporozoite; — can trigger the human immune system and help to protect against future infection. The only way to gather sporozoites, however, is to pluck them one-by-one from the salivary glands of irradiated, malaria-ridden mosquitoes. Then the parasites must be injected into people and you have to use a lot of them. This takes lots of time, lots of lab space and lots of people and it isn’t economically feasible for large-scale use.
Researchers from Rockefeller University and colleagues at New York University decided that fighting infection with infection might be the key. They began experimenting with the attenuated yellow fever strain used in the yellow fever vaccine, known as YF17D, which has been used to successfully vaccinate more than 400 million people since 1937. Previous work in the Rice laboratory and by others had shown that this vaccine strain could be modified to include short sequences from other pathogens, including malaria.
The researchers inserted the nearly complete sequence of a malaria gene into the YF17D vaccine and found that the malaria gene could produce its protein in cultured cells. The protein they chose, called CSP, covers the surface of the malaria sporozoite and is thought to be the main reason that this form of the parasite stimulates the immune system so effectively.
Immunization of mice with the YF17D-CSP vaccine led to a measurable jump in immune activity against the malaria protein, but the single shot was not enough to protect the animals from infection with the mouse form of the malaria parasite.
The group therefore added a booster shot to the vaccination regimen. Animals that had been immunized with YF17D-CSP, or with a saline solution control, were given a low dose of irradiated sporozoites. While the saline-sporozoite group was only partially protected from challenge with viable parasites, vaccination with YF17D-CSP plus the sporozoites protected 100 percent of the animals against infection.
"These results are exciting because they show the YF17D-CSP vaccine can prime the immune response against a malaria parasite," says lead author Cristina Stoyanov. Although the utility of this approach for human immunization is not yet clear, the team hopes that further studies in other animal models might eventually lead to an effective vaccine.
By inserting a gene for the malaria parasite into a vaccine that originally targeted yellow fever, scientists have shown they can boost the immune system’s response to infection in mice. (Credit: James Gathany/CDC)
Guam has the mosquito that carries malaria. All it takes is someone with malaria who comes here from somewhere else. Here’s hoping that this vaccine proves to be cheap and effective!
There’s also some news about a different vaccine that isn’t quite as positive. It highlights the point that sometimes humans meddle with things that they don’t quite understand and perhaps can’t control.
We all breathed a sigh of relief when one of the most dreadful scourges known to man was finally declared eliminated after a massive worldwide vaccination campaign. I’m referring, of course, to smallpox and I am one of the last U.S. citizens to receive a smallpox vaccination. They were no longer routinely given to Americans, but I was traveling to Southeast Asia where it had not been declared eradicated. Shortly after I made my trip, smallpox was declared officially eradicated worldwide and routine vaccinations for smallpox stopped. It turns out that may not have been such a good idea.
TWO BIRDS WITH ONE STONE?
Of course, they say that you stamp out one problem and another arises. That certainly was the case with smallpox because shortly after it was eradicated, the world witnessed another explosive killer disease: HIV or AIDS. Now, researchers have discovered that the two things just could be linked.
According to researchers who published their work in the open access journal BMC Immunology, the smallpox vaccination produces a five-fold reduction in HIV replication in the laboratory. They raise the possibility that the end of smallpox vaccination in the mid-20th century may have caused a loss of protection that contributed to the rapid contemporary spread of HIV.
There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the reuse of unsterilized needles and the contamination of early batches of polio vaccine. However, all of these have been either disproved or do not sufficiently explain the behavior of the HIV pandemic.
Smallpox immunization was gradually withdrawn from the 1950s to the 1970s following the worldwide eradication of the disease, and HIV has been spreading exponentially since approximately the same time period. The scientists propose that smallpox vaccination may confer protection against HIV by producing long-term alterations in the immune system, possibly including the expression of a certain receptor, CCR5, on the surface of a person’s white blood cells, which is exploited by both viruses.
Although the results are interesting, the researchers say they are very preliminary and it is far too soon to recommend the general use of smallpox vaccinations for fighting HIV.
So now we have two instances of using a bullet for one problem to kill a completely different. Here’s hoping they both work!
Photograph of a Nigerian child being immunized during the Smallpox Eradication and Measles Control Program of West Africa in 1960. (Credit: CDC/Dr. J.D. Millar)
Although we have the malaria mosquito here and most of us know at least one person living with HIV, the place that is the mother lode for both diseases is Africa and the poor countries there have no money to make even the most basic inroads into solving their medical crises. Another disease that is more of a problem here and also a big problem world-wide is diabetes. German researchers are trying to make an economic impact on another of the world’s great killers.
A CHEAP SHOT
There are 25 MILLION people in the U.S. with diabetes and you don’t need to be told that it’s the biggest killer on Guam. But India is the country with the most diabetics with over 50 million people. No one on Guam goes without insulin if they seek help, but that isn’t the case in developing countries. Now German scientists have developed a new method to cheaply produce insulin for the treatment of diabetes.
The researchers wanted to develop a new procedure to increase the yield of an insulin precursor from which the actual insulin can be obtained, and in this way reduce costs. They used a type of yeast to produce the building blocks to make insulin.
In the early 1980s, insulin was the first recombinant product approved by the FDA for human application. Today, human insulin is produced as a recombinant protein, using two major routes. One route involves the production of the insulin precursor using the bacterium Escherichia coli. The other route involves baker’s yeast Saccharomyces cerevisiae. The yeast product is easier to use because the yeast secretes a soluble insulin precursor into the culture medium. This makes it easier to collect.
The newly described method from Ursula Rinas and her group also uses this route but the yeast they used produces much more of the insulin precursor. Insulin produced with this new method is identical to human insulin. The researchers are also working on a method to produce a vaccine against dengue fever using the same system.
For most people in developing countries medicine is too expensive and insulin is often difficult to obtain and very expensive. The researchers hope that this new method of producing insulin will be used in developing countries to produce insulin that everybody can afford.
Taking new shots at old killers. Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about the frontiers of medicine and many other topics. Enjoy!