Where viruses and bacteria cause cancer

Strictly speaking, cancer is not contagious. But a fair number of cancers are clearly caused by viral or bacterial infections: lymphomas can be triggered by the Epstein-Barr virus, which also causes mononucleosis. Liver cancers can be caused by Hepatitis B and C. Cervical cancers can be caused by human papillomavirus, the major reason behind the development of a vaccine against it.  For some of these cancers, nearly 100% of the cases have an infectious link—when researchers check to see if a virus or bacterium is working in the tumor or has left signs of its presence in a patient’s blood, the answer is nearly always yes.

A new paper in The Lancet takes a look at the very best data on the prevalence of infection-caused cancers and comes up with some striking numbers. Overall, they estimate that 16% of cancer cases worldwide in 2008 had an infectious cause—2 million out of 12.7 million.

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The war between people and disease-causing pathogens is old as humanity itself. This has helped shaped our so-called behavioral immunity, which can lead us, for example, to automatically avoid people who are visibly sick. But it can also misfire; previous studies have shown that people with compromised immune systems (due to a recent illness), and even people who describe themselves as afraid of germs or susceptible to disease, are more likely to avoid and feel prejudiced toward otherwise healthy people who merely look different than them, like foreigners or immigrants.

It appears this prejudice can be reduced or erased by public health measures like vaccination or the simple act of washing your hands, according to a recent study in Psychological Science. In the study’s first experiment, conducted at the height of the 2009 H1N1 swine flu, researchers gathered a group of participants, some of whom had already received a vaccine against H1N1. They were then randomly broken into two groups, which I’ll call group A and group B (each had roughly equal numbers of vaccinated and non-vaccinated people). Group A read news articles describing the flu’s health effects and the vaccine’s effectiveness, in order to remind or “prime” them to the threat posed by the virus. Group B read no such articles. All participants then took a test that measures prejudicial attitudes towards immigrants. In group A, unvaccinated people were more prejudiced against immigrants than those who had received the vaccine. In the “unprimed” group B, there was no measurable difference.

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Human serum albumin is used in everything from vaccines to cell culture.

Human blood is in demand these days. Donor blood is required for transfusions, of course, but it also contains human serum albumin, a blood protein used to treat shock, severe burns, and liver injuries that also shows up in vaccines and in cell culture materials. Worldwide, we use about 500 tons of human serum albumin (abbreviated HSA) a year.

Shortages of the protein and the potential for contamination by blood-borne viruses have encouraged scientists to look beyond donor blood for sources. One promising approach, inserting the gene for HSA into plants and then harvesting the resulting protein, has always yielded too little for the method to make sense financially, but a new paper details a way to get around that: get the plant to make HSA in its seeds, which are lean, mean protein-concentrating machines. HSA made up 10% of the soluble protein in the rice seeds produced by the research team, one of the highest yields on record from a transgenic plant. And when the team put it through its chemical paces, it worked exactly like normal, human-grown HSA, indicating that its sojourn in the plant world hadn’t impaired its usefulness. If all goes as planned, the team will be testing rice-grown HSA in people in clinical trials in the next two years, with an eye towards supplanting donor blood as a source.

[via Nature News]

Image courtesy of Borislav Mitel / Wikimedia Commons

What’s the News: Researchers at the Scripps Research Institute have now created a vaccine that prevents a heroin high in rats. The vaccine, detailed in a recent study in the Journal of Medicinal Chemistry, stimulates antibodies that can stop not only heroin but also its derivative psychoactive compounds from reaching the brain.

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If a vaccine injures a child, should the parents be allowed to sue in state court? That’s a question lawyers, vaccine makers, parents, and Congress have wrestled over for a quarter century. This week, the United States Supreme Court brought forth a ruling that keeps the status quo: No, you can’t.

The justices, voting 6-2, said a 1986 federal law preempts claims that a drugmaker should have sold a safer formulation of a vaccine. The law, designed to encourage vaccine production by limiting patient suits, channels most complaints into a company- financed no-fault system that offers limited but guaranteed payments for injuries shown to be caused by a product. [Bloomberg]

The case in question, which has been kicking around for nearly two decades, was brought by Russell and Robalee Bruesewitz on behalf of their daughter, Hannah. In 1992 she began experiencing seizures after receiving a diphtheria, pertussis and tetanus shot made by  Wyeth [part of Pfizer]. At the time, her parents tried to file a claim with that government-created system.

When a special Vaccine Court within the Court of Federal Claims ruled that her injuries couldn’t be linked with the vaccine, her parents tried to move the case to Pennsylvania state court. The Third Circuit Court of Appeals eventually ruled that the claim was pre-empted by federal law, a decision upheld by the Supreme Court. [Wall Street Journal]

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By combining a cocaine analog with part of a common cold virus, researchers have created a “cocaine vaccine” that tricks the body into attacking the drug, neutralizing its high-giving powers. It has only been tested in mice so far, but the results are good:

“Our very dramatic data shows that we can protect mice against the effects of cocaine, and we think this approach could be very promising in fighting addiction in humans,” study researcher Ronald Crystal, a professor of genetic medicine at Weill Cornell Medical College, said in a statement. [LiveScience]

The immune system doesn’t typically react to cocaine in the blood stream–it’s too small and doesn’t contain the “markers” of an invader. To get the white blood cells to notice it, the researchers strapped it to something the immune system can detect–the outside parts of the virus. The researchers took the outer shell from an adenovirus, which causes some types of the common cold, and removed the parts of the virus that cause illness. Then they linked that recognizable viral shell to a stable molecule similar to cocaine (they also tried it with cocaine itself, the researchers say, but the more-stable analog produced better results).

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More than a dozen years have passed since the 1998 study in The Lancet in which researcher Andrew Wakefield argued his case that vaccines are the cause of autism. We here at DISCOVER have long considered his claims to be dubious and damaging to public health, but in the last few years the edifice upon which the anti-vaccination movement was built has been falling down. In 2004 most of the coauthors on the Wakefield study retracted the interpretation section of the paper, and early last year The Lancet officially retracted the entire paper. Now, this week, the British Medical Journal’s investigation calls Wakefield an out-and-out “fraud.”

From Phil Plait:

Of course, the word “fraud” implies intent; when writing about Wakefield I had my suspicions, but always wrote as if he were just wrong, and not deliberately lying to vulnerable parents.

But deliberate fraud is what he’s now accused of. Brian Deer, an investigative journalist, has written a multi-part series on the BMJ site which slams Wakefield. Fiona Godlee, BMJ’s editor-in-chief, also writes about this… and just to be clear, she uses the word “fraud” nine times in her editorial.

…

Brian Deer’s article on BMJ is nothing short of a tour-de-force, and is a horrifying tale of how Wakefield allegedly falsified medical research deliberately while operating under a huge conflict of interest. Deer’s article is meticulously referenced and footnoted… but still, I know this won’t stop the antivaxxers.

Read the rest of Phil’s post about this at Bad Astronomy.

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Image: iStockphoto

Goodbye and good riddance, rinderpest.

For only the second time in history, humans have eradicated a disease through a long, slogging campaign of vaccinations and global alertness.

Rinderpest, which means “cattle plague” in German, does not affect humans, though it belongs to the same virus family as measles. But for millenniums in Asia, Europe and Africa it wiped out cattle, water buffalo, yaks and other animals needed for meat, milk, plowing and cart-pulling. Its mortality rate is about 80 percent — higher even than smallpox, the only other disease ever eliminated. [The New York Times]

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From Ed Yong:

In 8 May 1980, the World Health Organisation declared that “the world and its peoples have won freedom from smallpox.” Through decades of intense vaccination, this once fatal disease had been wiped out. It was a singular victory and having won it, countries around the world discontinued the vaccination programmes. After all, why protect against a disease that no longer exists (save in a few isolated stocks)?

Unfortunately, this is not a rhetorical question. The smallpox vaccine did more than protect against smallpox. It also reduced the risk of contracting a related illness called monkeypox, which produces the same combination of scabby bumps and fever. It’s milder than smallpox but it’s still a serious affliction. In Africa, where monkeypox originates from, it kills anywhere from 1-10% of those who are infected. And more and more people are becoming infected.

Read the rest of this post at Not Exactly Rocket Science.

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Image: U.S. Air Force

Replacing a traditional needle with a fingernail-sized patch may one day make some immunizations painless and possibly more effective. A study published in Nature earlier this week shows that a patch–a square of “microneedles” that are too short to register a typical shot’s sting and that dissolve in the skin–effectively immunized mice against a strain of the flu virus.

The researchers have yet to test the patch on humans, and that next step could take a few years; the move from a successful animal trial to a human trial isn’t a small feat. Still, many see this patch’s promise. As Paul Offit, director of the Vaccine Education Center and chief of infectious diseases  at Children’s Hospital of Philadelphia, says:

“The caveat is, this needs to be extended to humans…. It’s not uncommon for vaccines or vaccine delivery systems to look very promising in experimental animals, then fail in humans. But there is every reason to believe this kind of technology could be applicable to children and adults.” [HealthDay News]

If the patch proves successful in human studies, here are some reasons it might quickly catch on.

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Some like it hot. The bacteria Francisella tularensis is among them. It likes to live at the temperatures present inside human bodies, and give us the disease tularaemia. But Barry Duplantis figured out a way to make the body an unattractive destination for the bacteria: He injected it with the genes of a cold-lover.

In a study in this week’s Proceedings of the National Academy of Sciences, Duplantis brought in Colwellia psycherythraea, a bacteria that can survive in the icy temperatures of the Arctic, but would die at a temperature like the nearly 100 degrees inside our bodies. By transferring genes responsible for that temperature sensitivity into F. tularensis, he created versions of that bacteria with lower heat tolerances.

When he injected these microbes into mice, they couldn’t migrate to warm areas like the lungs and do damage. Plus, the presence of the incapacitated bacteria acted as a sort of vaccine, putting the animals’ immune systems at the ready. When the researchers later gave the mice large exposures to unaltered F. tularensis, they didn’t get as sick as control mice.

For plenty more on this study, check out Ed Yong’s post at Not Exactly Rocket Science.

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Image: Richard Finkelstein

You can’t defeat what you can’t identify. That’s part of the human body’s problem with HIV–a virus that mutates constantly. Most antibodies can identify, latch onto, and neutralize only certain variants of the virus, or none at all. But two new studies published in Science yesterday point to two antibodies that almost always hits their targets--neutralizing some 90 percent of the most common HIV strains.

Scientists hope to eventually use their knowledge of these antibodies to develop a vaccine, but this is not an easy task.

“The path forward isn’t as clear as we’d like it to be, but we are turning a corner, I think,” says David Montefiori, a viral immunologist at Duke University Medical Center in Durham, N.C., who was not involved in the research. [Science News]

But first, how did they find these antibodies?

Step 1: Learning from a Survivor

Researchers at the National Institute of Allergy and Infectious Diseases looked at the blood of a 60-year-old African American man who had survived with HIV for 20 years.

The HIV antibodies were discovered in the cells of a 60-year-old African-American gay man, known in the scientific literature as Donor 45, whose body made the antibodies naturally…. Donor 45′s antibodies didn’t protect him from contracting HIV. That is likely because the virus had already taken hold before his body produced the antibodies. He is still alive, and when his blood was drawn, he had been living with HIV for 20 years. [Wall Street Journal]

Something about Donor 45′s antibodies were keeping the virus at bay or, more specifically, keeping it from binding with certain white blood cells to infect and destroy them.

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Yes, it’s in the early stages of research. And yes, it’s been tested only on mice. But the procedure developed by Vincent Tuohy and his team, billed as a preliminary breast cancer vaccine, has raised hopes once more that one day in the not-too-distant future such a procedure could be available for humans.

In a study this month in Nature Medicine, Tuohy tested the vaccine on mice genetically engineered to be more cancer-prone. The ones that received the full vaccine, with a protein called a-lactalbumin, didn’t develop breast cancer. All the others did.

Cancer presents a quandary that viruses don’t in terms of developing vaccines, experts point out. While viruses are recognized as foreign invaders by the immune system, cancer isn’t. Cancer is an over-development of the body’s own cells. Trying to vaccinate against such cell over-growth would effectively be vaccinating against the recipient’s own body, destroying healthy tissue [CBS News].

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With smallpox largely eradicated around the world, health organizations phased out the smallpox vaccine between the 1950s and 1970s (the last natural case of the disease was seen in 1977, in Somalia). During that span, Raymond Weinstein says, the AIDS crisis broke out in force. And in a study in BMC Immunology, he argues those two events could be connected.

Supposing that smallpox vaccination could have some effect on a person’s susceptibility to HIV, researchers led by Weinstein tested the idea on cells in a lab. They took immune cells from 10 people recently vaccinated against smallpox and 10 people never vaccinated. HIV, they found, was five times less successful at replicating with the cells of vaccinated people.

Why?

The researchers believe vaccination may offer some protection against HIV by producing long-term alterations in the immune system, possibly including the expression of a receptor called CCR5 on the surface of white blood cells, which is exploited by the smallpox virus and HIV [BBC News].

Any finding that expands knowledge of how HIV replicates could be an important one. And while this small study can’t prove Weinstein’s assertion is correct, the argument is, at the very least, plausible. Says Weinstein:

“There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the reuse of unsterilised needles and the contamination of early batches of polio vaccine. However, all of these have been either disproved or do not sufficiently explain the behaviour of the HIV pandemic” [Press Association].

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Image: CDC

Yesterday the Food and Drug Administration gave its OK to Provenge, a new treatment for prostate cancer. It’s not a “vaccine” in the old-fashioned sense, but it could be a way to make the immune system wake up and take notice to the presence of cancer.

In a standard vaccination, a person receives an attenuated or dead version of a microorganism to spur them to produce antibodies (against, for example, the virus that causes smallpox). Provenge is not that—it doesn’t prevent prostate cancer—but it is a variation on the theme. To oversimplify quite a bit: with Provenge vaccination begins with a blood draw. Blood is then sent to the lab, where technicians extract immune cells known as antigen presenting cells (APCs) from the sample. From here, Dendreon combines the immune cells with proteins that are prevalent on the surface of prostate cancer cells. An immune boosting substance is also added into the mix [TIME]. That awakens the APCs, which doctors then inject back into the bloodstream. And once there, the APCs put white blood cells on high alert against cancer.

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