(Press-News.org) CAMBRIDGE, Mass.- MIT engineers have designed a new type of nanoparticle that could safely and effectively deliver vaccines for diseases such as HIV and malaria.
The new particles, described in the Feb. 20 issue of Nature Materials, consist of concentric fatty spheres that can carry synthetic versions of proteins normally produced by viruses. These synthetic particles elicit a strong immune response — comparable to that produced by live virus vaccines — but should be much safer, says Darrell Irvine, author of the paper and an associate professor of materials science and engineering and biological engineering.
Such particles could help scientists develop vaccines against cancer as well as infectious diseases. In collaboration with scientists at the Walter Reed Army Institute of Research, Irvine and his students are now testing the nanoparticles' ability to deliver an experimental malaria vaccine in mice.
Vaccines protect the body by exposing it to an infectious agent that primes the immune system to respond quickly when it encounters the pathogen again. In many cases, such as with the polio and smallpox vaccines, a dead or disabled form of the virus is used. Other vaccines, such as the diphtheria vaccine, consist of a synthetic version of a protein or other molecule normally made by the pathogen.
When designing a vaccine, scientists try to provoke at least one of the human body's two major players in the immune response: T cells, which attack body cells that have been infected with a pathogen; or B cells, which secrete antibodies that target viruses or bacteria present in the blood and other body fluids.
For diseases in which the pathogen tends to stay inside cells, such as HIV, a strong response from a type of T cell known as "killer" T cell is required. The best way to provoke these cells into action is to use a killed or disabled virus, but that cannot be done with HIV because it's difficult to render the virus harmless.
To get around the danger of using live viruses, scientists are working on synthetic vaccines for HIV and other viral infections such as hepatitis B. However, these vaccines, while safer, do not elicit a very strong T cell response. Recently, scientists have tried encasing the vaccines in fatty droplets called liposomes, which could help promote T cell responses by packaging the protein in a virus-like particle. However, these liposomes have poor stability in blood and body fluids.
Irvine, who is a member of MIT's David H. Koch Institute for Integrative Cancer Research, decided to build on the liposome approach by packaging many of the droplets together in concentric spheres. Once the liposomes are fused together, adjacent liposome walls are chemically "stapled" to each other, making the structure more stable and less likely to break down too quickly following injection. However, once the nanoparticles are absorbed by a cell, they degrade quickly, releasing the vaccine and provoking a T cell response.
In tests with mice, Irvine and his colleagues used the nanoparticles to deliver a protein called ovalbumin, an egg-white protein commonly used in immunology studies because biochemical tools are available to track the immune response to this molecule. They found that three immunizations of low doses of the vaccine produced a strong T cell response — after immunization, up to 30 percent of all killer T cells in the mice were specific to the vaccine protein.
That is one of the strongest T cell responses generated by a protein vaccine, and comparable to strong viral vaccines, but without the safety concerns of live viruses, says Irvine. Importantly, the particles also elicit a strong antibody response.
In addition to the malaria studies with scientists at Walter Reed, Irvine is also working on developing the nanoparticles to deliver cancer vaccines and HIV vaccines. Translation of this approach to HIV is being done in collaboration with colleagues at the Ragon Institute of MIT, Harvard and Massachusetts General Hospital. The institute, which funded this study along with the Gates Foundation, Department of Defense and National Institutes of Health, was established in 2009 with the goal of developing an HIV vaccine.
###
Written by Anne Trafton, MIT News Office
END
WASHINGTON -- Infants and toddlers can suffer serious mental health disorders, yet they are unlikely to receive treatment that could prevent lasting developmental problems, according to research published by the American Psychological Association.
One barrier to mental health care for young children is "the pervasive, but mistaken, impression that young children do not develop mental health problems and are immune to the effects of early adversity and trauma because they are inherently resilient and 'grow out of' behavioral problems and emotional difficulties," according ...
It may seem paradoxical, but being part of a crowd is what makes you unique, according to UCLA life scientists.
Biologists Kimberly Pollard and Daniel Blumstein examined the evolution of individuality —personal uniqueness — by recording alarm-call vocalizations in eight species of rodents that live in social groups of various sizes. They found that the size of the groups strongly predicted the individual uniqueness in the animals' voices: The bigger the group, the more unique each animal's voice typically was and the easier it was to tell individuals apart.
Their ...
CORVALLIS, Ore. – The terribly destructive earthquake that just hit Christchurch, New Zealand, was only a moderate 6.3 magnitude, but had certain characteristics that offer an important lesson to cities up and down the West Coast of North America that face similar risks, experts say.
The New Zealand earthquake killed dozens – and some fear the death toll may rise to the hundreds – and was an aftershock of the much more powerful 7.1 magnitude earthquake that struck that nation last September near the same area, but caused no deaths.
Even though this earthquake was weaker ...
Ignoring the stresses of an unemployed spouse's job search does not bode well for the employed spouse's job productivity or home life, says a University of Colorado Boulder professor.
Associate Professor Maw-Der Foo of CU-Boulder's Leeds School of Business studies employee workplace issues, including those related to interpersonal relationships.
Foo and lead author Professor Zhaoli Song of the National University of Singapore co-authored a paper titled "Unraveling the Stress Crossover Between the Unemployed and Their Spouses," which was published in last month's edition ...
Alexandria, VA – In the back alleys of the world's capitals and the ballrooms of presidential palaces exists a black market that preys on the imagination of some and the greed of others. These black-market items are not of this world: They are moon rocks, collected decades ago by six Apollo missions and three unmanned Soviet missions to the moon.
For the past decade, former NASA investigator Joseph Gutheinz Jr. has been tracking this lunar larceny - with a good bit of success. In the March feature "A Memoir: A Decade-Plus of Tracking Lunar Larceny," Gutheinz recalls some ...
Wildlife conservation strategies may better protect mammals from human activities by treating animals' ranges as multiple interacting small populations, a study finds. Charles Yackulic and colleagues analyzed historical range maps for 47 mammal species to find patterns that might help conservationists assess threats to animal populations from human encroachment. According to the authors, an animal's habitable range contains different ecological niches that can provide valuable clues about the species resiliency. Local environmental factors such as temperature and precipitation ...
TORONTO, Ont., Feb, 23, 2011—Women who take commonly prescribed drugs for osteoporosis known as bisphosphonates for five years or more may be at higher risk of certain kinds of fractures of their thigh bone, a new study has found.
However, the drugs do prevent hip fractures. And, since the overall risk of thigh bone fractures caused by the drugs is low, women at high risk for hip and other osteoporosis-related fractures should not stop taking bisphosphonates, according to researchers at St. Michael's Hospital and the Institute for Clinical Evaluative Sciences.
The study ...
Madison, WI FEBRUARY 10, 2011 – Finding employment can be a daunting task. Millions of college graduates, new to the professional work force, face this challenge every year after receiving their degrees. Many have sacrificed and toiled for perfect grades, worked at internships to prepare for careers, and filled their schedules with university affiliated clubs and activities. The belief that these attributes will enhance a resume and impress an employer is widespread, but does it really reflect what employers seek in a new hire?
To answer this question, researchers at ...
CHICAGO --- Paid caregivers make it possible for seniors to remain living in their homes. The problem, according to a new Northwestern Medicine study, is that more than one-third of caregivers had difficulty reading and understanding health-related information and directions. Sixty percent made errors when sorting medications into pillboxes.
The study will be published in the Journal of General Internal Medicine. It has been published online.
In a first-of-its-kind study, nearly 100 paid, non-family caregivers were recruited in the Chicago area and their health literacy ...
Researchers at the University of Illinois at Chicago have discovered a signaling mechanism in the bacterial ribosome that detects proteins that activate genes for antibiotic resistance.
"The ribosome is one of the most complex molecular machines in the cell," said Alexander Mankin, UIC professor and director of the Center for Pharmaceutical Biotechnology. It is responsible for the production of all proteins in the cell, and in bacteria it is one of the major antibiotic targets.
Understanding how signals are generated and transmitted within the ribosome, Mankin said, ...
