the effects of bad science

Vaccination

A new epidemic of measles has broken out in Wales. Vaccination rates fell after a paper linking the vaccine to autism was published in the 1998. The paper was later proven to be fraudulent. NPR reports:

More than 1,200 people have come down with measles so far this year, following nearly 2,000 cases in 2012. Many of the cases have been in Wales.

Childhood vaccination rates plummeted in Great Britain after a 1998 paper by Dr. Andrew Wakefield claimed that the vaccine for measles, mumps and rubella had caused autism in a dozen children. That study has since been proven , but it fueled fears about vaccine safety in Great Britain and the United States.

“This is the legacy of the Wakefield scare,” Dr. David Elliman, spokesman for the Royal College of Pediatrics and Child Health, told The Associated Press.

Most of the measles cases have been in children and teenagers between the ages of 10 and 18, according to British health officials. In that age group, vaccination rates dropped below 50 percent in some parts of England after the Wakefield paper was published.

HIV testing by DVD

A recent paper in Lab on a Chip describes using a DVD player as a diagnostic tool. The researchers convert the optical drive into a laser scanning device that can count the number of CD4+ cells. From Phys Org:

Aman Russom, senior lecturer at the School of Biotechnology at KTH Royal Institute of Technology in Stockholm, says that his research team converted a commercial DVD drive into a laser scanning microscope that can analyse blood and perform cellular imaging with one-micrometre resolution. The breakthrough creates the possibility of an inexpensive and simple-to-use tool that could have far-reaching benefits in health care in the developing world.

“With an ordinary DVD player, we have created a cheap analytical tool for DNA, RNA, proteins and even entire cells,” says Russom. The so-called “Lab-on-DVD” technology makes it possible to complete an HIV test in just a few minutes, he says.

In a proof of concept demonstration, the researchers collected cell-type CD4 + from blood and visualized it using the DVD reader technology. Enumeration of these cells using flow cytometry is now standard in HIV testing, but the practice has been limited in developing countries.

HIV testing currently uses flow cytometry, which requires expensive equipment. If the DVD technique proves reliable, HIV testing can be done much more cheaply.

hollow vaccines

Popular Science highlights this paper from PLOS Pathogens. The research discusses creating hollowed out versions of viral capsids. These capsids would stimulate the immune system to produce antibodies without any potential for infection since the virus’ genetic material has been removed.

Call it hollow-hearted. Researchers have built a mimic of the outer capsule of the foot-and-mouth disease virus. Inside, where the virus’ genetic material normally lives, is empty.

Such synthetic virus-like particles could go into a foot-and-mouth vaccine that’s cheaper to make because it doesn’t require the tight biosecurity that a factory that makes vaccines from live viruses needs, its creators say. The researchers have also built the virus mimic in such a way that it can stay out of a refrigerator for longer than current foot-and-mouth vaccines, so it could ship more easily around the world.

In the future, the same techniques could apply to vaccines to the polio virus, which belongs to a large group of viruses related to hoof-and-mouth, Andrew Macadam, a polio researcher at the U.K. National Institute for Biological Standards and Control, told the BBC. Polio vaccines are now made with either weakened or killed polio viruses. (The weakened type still carries a small risk of reverting to its original form and causing paralysis. That vaccine is no longer used in the U.S., but some other countries give it out because it doesn’t require a highly trained medical professional to administer.)

The researchers hope it will lead to cheaper and less risky vaccines.

adults cured of HIV

HIV Medications

A new report in PLoS Pathogens reports that in 14 adults are have been functionally cured of HIV. This comes after a Mississippi baby was miraculously cured of HIV because of early treatment. Early antiretroviral treatment seems to be important in these cases as well. From a summary in The New Scientist:

Asier Sáez-Cirión of the Pasteur Institute’s unit for regulation of retroviral infections in Paris analysed 70 people with HIV who had been treated with antiretroviral drugs (ARVs) between 35 days and 10 weeks after infection – much sooner than people are normally treated.

All of the participants’ drug regimes had been interrupted for one reason or another. For example, some people had made a personal choice to stop taking the drugs, others had been part of a trial of different drug protocols.

Most of the 70 people relapsed when their treatment was interrupted, with the virus rebounding rapidly to pre-treatment levels. But 14 of them – four women and 10 men – were able to stay off of ARVs without relapsing, having taken the drugs for an average of three years.

The 14 adults still have traces of HIV in their blood, but at such low levels that their body can naturally keep it in check without drugs.

The 14 adults are not naturally resistant to HIV infection and are not currently taking any medication to control their HIV.

CD4 cells are instrumental in controlling HIV infection

HIV medication

A report in Science discusses how a subset of CD4 cells could prevent HIV from destroying the immune system:

HIV preferentially invades T lymphocytes that have CD4 receptors on their surfaces. The resulting destruction of CD4 cells over a decade or so cripples the immune system and is the hallmark of AIDS. But the process takes many years because the central memory cell, a type of CD4+ T lymphocyte known in shorthand as T_cm, churns out clones of itself and can almost refill the body’s pool of CD4 cells as fast as HIV drains it. However, the downside is that some infected T_cm cells become reservoirs of latent virus that rekindle infection if antiretrovirals (ARVs) are stopped.

The report is based on a series of studies of HIV patients. In the first study 75 HIV patients were split into three different groups and received antiretroviral medications within 5 days of taking a blood test. When their blood was analyzed 24 weeks later, the level of HIV-infected T_cm cells was almost extremely low or undetectable. In another study researchers looked at why some patients were better able to protect their CD4+ cells without antiretroviral treatment:

The study compared nearly 300 infected people who had low levels of HIV in their blood, two-thirds of whom received treatment. The researchers found that elite controllers stood out in part because their T_cm cells downregulated a key receptor that HIV needs for entry and were less permissive to HIV infection. Conversely, Kitchen noted that people whose immune systems did not rebound even though ARVs controlled their infections had T_cm cells with impaired function.

Check the source link for more.

salt linked to autoimmune disease

Salt has been linked to the production of TH17 cells by the immune system.

Yesterday, Nature published three research papers announcing that researchers have found a link to salt intake and autoimmune diseases like multiple sclerosis and lupus. In two of the papers, researchers were studying how TH17 cells in the immune system get switched on. These cells are a type of helper T cell that produces an inflammatory protein called interleukin-17 as part of the immune response. While looking for different triggers, the researchers discovered that TH17 activation was linked to the production of a protein called serum glucocorticoid kinase 1, or SGK1, that helps maintain salt levels in other cells. The researchers then saw that mice on a high salt diet had higher levels of SGK1 and more TH17 cells. From Scientific American:

The researchers found that mouse cells cultured in high-salt conditions had higher SGK1 expression and produced more TH17 cells than those grown in normal conditions.

“If you incrementally increase salt, you get generation after generation of these TH17 cells,” says study co-author Vijay Kuchroo, an immunologist at Brigham and Women’s Hospital in Boston, Massachusetts.

The research was then confirmed using a mouse model for multiple scelerosis and in vitro human cell culture. Again from Scientific American:

In the third study, researchers confirmed Kuchroo’s findings, in mouse and human cells. It was “an easy experiment — you just add salt”, says David Hafler, a neurologist at Yale University in New Haven, Connecticut, who led the research.

But could salt change the course of autoimmune disease? Both Kuchroo and Hafler found that in a mouse model of multiple sclerosis, a high-salt diet accelerated the disease’s progression.

All this evidence, Kuchroo says, “is building a very interesting hypothesis [that] salt may be one of the environmental triggers of autoimmunity”.

Whether this holds true in vivo for humans remains to be seen. It’s hard to generalize from in vitro cell culture as the immune system is highly regulated and that regulation can’t be simulated in a culture dish. And as I mentioned earlier this week, in many cases mouse models aren’t always good predictors for human systems.

breast feeding promotes development of gut bacteria

Gut bacteria

The New York Times describes an experiment on how gut bacteria develop in infancy:

Seeking to understand how the microbes are developed in early life, a team of Canadian researchers collected samples (dirty diapers, frozen) from newborns at birth and again at 3 months. They found that many children who were delivered by C-section all but lacked a group of critical bacteria found in those who were delivered vaginally. The gut bacteria in children who were fed only formula, rather than breast milk, was also significantly different from those who were given at least some breast milk.

a new tuberculosis vaccine falls short

Tuberculosis bacteria

A new study of the potential tuberculosis vaccine, modified Vaccinia Ankara virus expressing antigen 85A (MVA85A), has failed in a study of 3000 infants in South Africa. Scientists had hoped it would help improve protection against the infection when used with the current vaccination (BCG). The study was a double-blind, randomised, placebo-controlled trial of healthy infants (aged 4—6 months). The infants were randomly administered BCG with either MVA85A or a placebo of Candida skin test antigen then examined every 3 months for up to 3 years. During the course of the trial, the rates of serious or systemic infection from tuberculosis were similar for the group that received the new vaccine enhancer compared to those given the placebo. The researchers did note that the MVA85A does appear to be safe and that no adverse effects were cause by the antigen itself. This was the first efficacy trial of a tuberculosis vaccine in infants in more than 45 years. More details here at The Lancet [subscription required].

antibiotics in panda blood

Researchers have discovered a powerful antibiotic in the bloodstream of giant pandas. From The Telegraph:

Scientists have discovered that the animals, of which there are around 1,600 in the wild, produce a powerful antibiotic in their blood stream that kills bacteria and fungi.

They believe the substance could be used to create potent new treatments against drug resistant superbugs and other diseases.

The antibiotic is thought to be released by the bear’s immune system to protect them infections when they are living in the wild. Researchers discovered the compound, known as cathelicidin-AM, after analysing the panda’s DNA.

…

The Chinese researchers found that the cathelicidin-AM, which is produced by immune cells in the animal’s blood, was found to kill bacteria in less than an hour while other well known antibiotics took more than six hours.

Ed Yong lists reasons why no new drugs will likely come from the discovery.

engineered algae

Green algae.

Scientists are trying to figure out a way to reduce costs of producing targeted cancer treatments. Popular Science highlights a research group who engineered algae to produce and antibody conjugated with a fragment of the toxic protein, exotoxin A, from P. aeruginosa.

But recently, a group of scientists at University of California, San Diego engineered algae to produce a human antibody with a built-in toxic weapon–a ready-made molecular cancer assassin. The researchers produced the new therapy by embedding the genetic code of the toxin P. aeruginosa into a human antibody gene, which they then spliced into the algae’s DNA.

In their research paper, the scientists note that this feat has been attempted before, using bacteria instead of algae, but the bacteria weren’t capable of folding the complex antibody into the right shape, so the method required a researcher to follow along behind and refold the proteins. The new therapy could not be produced by mammal cells, either, the researchers write, because the presence of the toxin would prohibit the engineered cells from reproducing.

If the new treatment is able to stand up to the battery of medical trials required by law, the targeted, assassin-style fight against cancer may soon get a lot more affordable.

More here and here.