Enzyme that change a person’s blood type

Blood Type

Blood Type

Scientists have discovered that a particular type of enzyme can cut away antigens in blood types A and B, to make them more like Type O – considered the ‘universal’ blood type, because it’s the only type that can be donated to anyone without the risk of provoking a life-threatening immune response.

The team, from the University of British Columbia of Canada, worked with a family of enzymes called 98 glycoside hydrolase, extracted from a strain of Streptococcus pneumoniae. Over many generations, they were able to engineer a super high-powered enzyme strain that can very effectively snip away blood antigens where previous generations of the enzyme struggled. “A major limitation has always been the efficiency of the enzymes,” one of the team, Stephen Withers, said in a press release. “Impractically large amounts of enzyme were needed.”

Getting the right type of blood when you need it is crucial, and it has to do with the different types of residue that can accumulate the surface of red blood cells. Both blood types A and B have this residue – A has an N-acetylgalactosamine residue, and B has a galactose residue – and Type AB has a mixture of both. Only Blood Type O is free from this residue, which means it can be received by any patient, no matter what type they’re carrying.

Withers and his team managed to create their ‘mutant’ enzyme strain using a technology called directed evolution, which allows them to insert many different types of mutations into the gene that codes for it, and by progressively selecting strains that are the best at snipping away the blood antigens, were able to create an enzyme that’s 170 times more effective at it than its parent strain. They published their results in the Journal of the American Chemical Society.

“The concept is not new, but until now we needed so much of the enzyme to make it work that it was impractical,” said Withers. “Now I’m confident that we can take this a whole lot further.”

While the current enzyme strain is not yet capable of removing 100 percent of the antigens from Blood Types A and B, which is where it needs to get if the researchers want to make any real use of it, the team is confident that they’ll get it there so they can try it out in clinical trials. Even the smallest amount of antigen in donated blood can set off a dangerous immune response in the recipient.

“Given our success so far, we are optimistic that this will work,” says Withers.

Source:  sciencealert.com

Alcohol Consumption Boosts Body’s Immune System

Moderate Alcohol Consumption Boosts Body’s Immune System, Study Suggests

Moderate Alcohol Consumption Boosts Body's Immune System, Study Suggests

Moderate Alcohol Consumption Boosts Body’s Immune System, Study Suggests

The scientists did their research in rhesus macaques, which have an immune system very similar to humans. To conduct the study, the researchers trained a group of 12 rhesus macaques to consume alcohol — a 4 percent ethanol mixture — of their own accord.

Researchers vaccinated the monkeys against small pox as part of the study. They then separated the animals into two groups — those with access to the 4 percent ethanol and those with access to sugar water. All of the animals had regular access to pure water, and to food.

The researchers then monitored the animals’ daily ethanol consumption for 14 months. And the animals were vaccinated again, seven months after the experiment began.

“Like humans, rhesus macaques showed highly variable drinking behavior,” said Ilhem Messaoudi, the lead author of the paper, a former assistant professor at the Vaccine and Gene Therapy Institute at OHSU and assistant scientist in the Division of Pathobiology and Immunology at the Oregon National Primate Research Center and now an associate professor of biomedical sciences at the University of California, Riverside. “Some animals drank large volumes of ethanol, while others drank in moderation.”

The monkeys’ voluntary ethanol consumption segregated them into two groups. One group was made up of heavy drinkers, those that had an average blood ethanol concentration greater than 0.08 percent — the legal limit for humans to be able to drive a vehicle. The other group was made up of moderate drinkers, with an average blood ethanol concentration of 0.02 to 0.04 percent.

Prior to consuming the alcohol, all of the animals showed comparable responses to the vaccination. But after exposure to the alcohol, the two groups of monkeys responded in very different ways to the vaccination.

The heavy drinkers showed greatly diminished vaccine responses compared with the control group of monkeys who drank the sugar water. But the more surprising finding: the moderate-drinking monkeys displayed enhanced responses to the vaccine compared to the control group. Moderate drinking bolstered their bodies’ immune systems.

The researchers stressed that excessive alcohol consumption was injurious to the monkeys’ immune systems — just as excessive alcohol consumption is bad for human bodies in many ways.

“If you have a family history of alcohol abuse, or are at risk, or have been an abuser in the past, we are not recommending you go out and drink to improve your immune system,” Messaoudi said. “But for the average person who has, say, a glass of wine with dinner, it does seem in general to improve health and cardiovascular function. And now we can add the immune system to that list.”

The next steps for the researchers will be to better understand why the immune system reacts as it does to moderate alcohol. That may lead to a pharmaceutical alternative that could provide the same benefits as the moderate alcohol consumption.

Scientists snap picture of immune system

Scientists snap the clearest picture yet of the immune system in action:

Scientists snap the clearest picture yet of the immune system in action.

Scientists snap the clearest picture yet of the immune system in action.

A microscope powerful enough to capture a single molecule has taken the clearest picture yet of the immune system in action.

The technique, called superresolution single-molecule fluorescence microscopy, recently helped scientists at the University of Manchester in England track natural killer (NK) cells, which help destroy cancer and viruses.

NK cells have receptors that are clustered together at their surface, and these receptors target proteins on another cell’s surface to tell whether the contacting cell is diseased or healthy. When the NK cell is activated, the receptor clusters change in size and density, which could help NK cells recognize and eliminate infected cells — but spare healthy ones — next time around.

Vaccine trial reveals HIV target

Analysis identifies target for immune response that could improve AIDS vaccines:

Vaccine trial reveals chinks in HIV's armour  Analysis identifies target for immune response that could improve AIDS vaccines.

Vaccine trial reveals chinks in HIV’s armour
Analysis identifies target for immune response that could improve AIDS vaccines.

HIV is finally revealing its weak spots to researchers, bringing an effective vaccine against AIDS closer to reality. A paper published in Nature today1 sheds light on how a vaccine can turn the immune system against the invading virus and so offer protection from infection. The results are also being presented at the AIDS Vaccine 2012 conference in Boston, Massachusetts, this week. The findings help to explain the results from a clinical trial of an AIDS vaccine that have puzzled researchers since they were published three years ago2. The trial, called RV144, was the first to score a success and see a reduction in HIV infections. But the vaccine’s relatively low response rate of 31% left researchers scratching their heads. A clue emerged last year with the revelation that those who responded to the vaccine and fended off HIV tended to produce antibodies against a specific part of the virus’s protein shell called the V1/V2 loop. The study published today goes a stage further, showing that the people who were vaccinated yet still contracted HIV had been infected by viruses that had mutations in the the V2 portion. “This is a really good paper,” says Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland. “It adds to the growing body of information indicating that an immune response against components of the V1/V2 loop is important in vaccine-induced protection against infection.” The team behind the study was led by Morgane Rolland and Jerome Kim at the US Military HIV Research Program in Silver Spring, Maryland. They examined 936 HIV sequences collected from 44 trial participants who received the vaccine and became infected, and 66 people who got the placebo. The trial was randomized, so any systematic differences in the viral DNA sequences between the two groups will be due to selective pressure by the vaccine in favour of viruses that do not match the vaccine, Rolland says. The team identified two mutations that seemed to be linked to vaccination success. Both were located in the V2 region of the V1/V2 loop. Rolland and Kim’s team compared the rates of infection with viruses whose sequence varied at these two sites between people who received the vaccine and those who got a placebo. People who received the vaccine were 80% less likely to be infected by viruses with these mutations, compared to people who got a placebo. The implication is that the vaccine triggered an immune response that prevented certain viruses from infecting them, and only viruses with different sequences at those two sites had a good chance of creating an infection. Another study, led by researchers at NIAID, to be presented at the vaccine conference this week analysed the molecular structure of antibodies from the blood of vaccinated people and found that some of their antibodies recognized the same amino acids in the V2 region. The question facing vaccine developers now is how to improve the response against V2. A vaccine similar to that used in RV144 is set to be tested in South Africa and among men who have sex with men in Thailand in two trials that will begin around 2014. Scientists hope that giving a booster within a year of the first jab and a new adjuvant will lead to a stronger and longer-lasting response against HIV and its V2 region, says Kim who is helping to design the trials. Mounting a response against V2 “isn’t the whole answer to vaccine protection”, says Fauci, but “you can be darn sure people are going to figure out how to rev it up”.