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Posts Tagged ‘vaccine’

Vaccine triggers immune response, prevents Alzheimer’s

A vaccine created by University of Rochester Medical Center scientists prevents the development of Alzheimer’s disease-like pathology in mice without causing inflammation or significant side effects.

Vaccinated mice generated an immune response to the protein known as amyloid-beta peptide, which accumulates in what are called “amyloid plaques” in brains of people with Alzheimer’s. The vaccinated mice demonstrated normal learning skills and functioning memory in spite of being genetically designed to develop an aggressive form of the disease.

The Rochester scientists reported the findings in an article in the May issue of Molecular Therapy, the journal of The American Society of Gene Therapy.

“Our study demonstrates that we can create a potent but safe version of a vaccine that utilizes the strategy of immune response shaping to prevent Alzheimer’s-related pathologies and memory deficits,” said William Bowers, associate professor of neurology and of microbiology and immunology at the Medical Center and lead author of the article. “The vaccinated mice not only performed better, we found no evidence of signature amyloid plaque in their brains.”

Alzheimer’s is a progressive neurodegenerative disease associated with dementia and a decline in performance of normal activities. Hallmarks of the disease include the accumulation of amyloid plaques in the brains of patients and the loss of normal functioning tau, a protein that stabilizes the transport networks in neurons. Abnormal tau function eventually leads to another classic hallmark of Alzheimer’s, neurofibrillary tangle in nerve cells. After several decades of exposure to these insults, neurons ultimately succumb and die, leading to progressively damaged learning and memory centers in the brain.

The mice that received the vaccines were genetically engineered to express large amounts of amyloid beta protein. They also harbored a mutation that causes the tau-related tangle pathology. Prior to the start of the vaccine study, the mice were trained to navigate a maze using spatial clues. They were then tested periodically during the 10-month study on the amount of time and distance traveled to an escape pod and the number of errors made along the way.

“What we found exciting was that by targeting one pathology of Alzheimer’s — amyloid beta — we were able to also prevent the transition of tau from its normal form to a form found in the disease state,” Bowers said.

The goal of the vaccine is to prompt the immune system to recognize amyloid beta protein and remove it. To create the vaccine, Bowers and the research group use a herpes virus that is stripped of the viral genes that can cause disease or harm. They then load the virus container with the genetic code for amyloid beta and interleukin-4, a protein that stimulates immune responses involving type 2 T helper cells, which are lymphocytes that play an important role in the immune system.

The research group tested several versions of a vaccine. Mice were given three injections of empty virus alone, a vaccine carrying only the amyloid beta genetic code, or a vaccine encoding both amyloid beta and interlueikin-4, which was found to be the most effective.

“We have learned a great deal from this ongoing project,” Bowers said. “Importantly, it has demonstrated the combined strengths of the gene delivery platform and the immune shaping concept for the creation of customized vaccines for Alzheimer’s disease, as well as a number of other diseases. We are currently working on strategies we believe can make the vaccine even safer.”

Bowers expects the vaccine eventually to be tested in people, but due to the number of studies required to satisfy regulatory requirements, it could be three or more years before human trials testing this type of Alzheimer’s vaccine occur.

Source: University of Rochester Medical Center

Reduced Pathology and Improved Behavioral Performance in Alzheimer’s Disease Mice Vaccinated With HSV Amplicons Expressing Amyloid-beta and Interleukin-4. Maria E Frazer, Jennifer E Hughes, Michael A Mastrangelo, Jennifer L Tibbens, Howard J Federoff and William J Bowers. Mol Ther 16: 845-853

Josh says:

This is fantastic. I see no reason why this can’t also be applied to other similar diseases. I wonder if the same technique could be used for prion diseases like mad cow disease.

New technology for boosting vaccine efficiency

One of the most pressing biomedical issues is the development of techniques that increase the efficiency of vaccines. In a paper published on April 24, 2008 in the journal Vaccine, a Massachusetts’s biotechnology company, Cure Lab, Inc. has proposed a new technology for anti-viral vaccination. This technology consists of two major elements. First, each vaccine antigen should be made in two forms. One is easily processed within the organism’s cells by an intracellular “chopping machine” called the proteosome, while another is resistant to the “chopping”. Thus both these forms of an antigen would be used in combination to elicit a much stronger immune response than either of them would be able to do alone.

Imagine a vaccine that could make a cell within our body produce a viral protein. This is called a recombinant vaccine. Recombinant vaccines give the most hope today as anti-viral and anti-cancer vaccines. They train the immune system to recognize and eliminate first infected or cancerous cells, preventing a disease progression. In order for a recombinant vaccine to be effective, the produced viral protein must be presented by the cell to our immune system. This antigen presentation process is very complex and remains poorly understood. … Continue Reading »

Alzheimer’s vaccine clears plaque but has little effect on learning and memory impairment

A promising vaccine being tested for Alzheimer’s disease does what it is designed to do — clear beta-amyloid plaques from the brain — but it does not seem to help restore lost learning and memory abilities, according to a University of California, Irvine study.

The findings suggest that treating the predominant pathology of Alzheimer’s disease — beta-amyloid plaques — by itself may have only limited clinical benefit if started after there is significant plaque growth. However, a combination of vaccination with therapies that also target related neuron damage and cognitive decline may provide the best treatment opportunity for people with this neurodegenerative disease. Study results appear in the April 2 issue of the Journal of Neuroscience. … Continue Reading »

Clinical trial will test new HIV/AIDS vaccine

A phase 1 clinical trial to test a novel HIV/AIDS vaccine has begun at Brigham and Women’s Hospital (BWH). This new vaccine aims to overcome the problem of preexisting immunity to common vaccine vectors, which is thought to be a major problem in the developing world.

“This study will involve 48 healthy volunteers who will receive either two or three immunizations and who will be followed to assess the safety and immunogenicity of the vaccine,” explains Lindsey R. Baden, MD, Assistant Professor of Medicine at BWH and Harvard Medical School and Protocol Chair for the study.

The vaccine consists of a replication-incompetent, recombinant adenovirus serotype 26 (rAd26) vector encoding an HIV-1 envelope gene. … Continue Reading »

Vaccine for Ebola virus

One of the world’s deadliest diseases, caused by the Ebola virus, may finally be preventable thanks to US and Canadian researchers, who have successfully tested several Ebola vaccines in primates and are now looking to adapt them for human use.

Dr Anthony Sanchez, from the Centers for Disease Control & Prevention in Atlanta, Georgia is presenting an overview of Ebola vaccine development today (Monday 31 March 2008) at the Society for General Microbiology’s 162nd meeting being held this week at the Edinburgh International Conference Centre.

“The biothreat posed by Ebola virus cannot be overlooked. We are seeing more and more naturally occurring human outbreaks of this deadly disease. With worldwide air travel and tourism the virus can now be transported to and from remote regions of the world. And it has huge potential as a possible weapon of bioterrorism”, says Dr Sanchez. “We desperately need a protective vaccine”. … Continue Reading »

Potential HIV Vaccine

Researchers at the Scripps Research Institute have developed a new strategy for making an HIV vaccine. They found that upon HIV infection, the HIV virus binds to dendritic cells. Dendritic cells are immune system cells that act like guards in skin and organ linings. If a potential threat is detected, these cells travel to the lymphatic system to initiate an adaptive immune system response. Unfortunately, when these infected dendritic cells travel to the lymphatic system, they also unwittingly transport the HIV virus to its ultimate destination: the immune system’s T-cells.

Leveraging this discovery, the Scripps Research team’s experimental HIV defense works in two ways:

  1. An artificial block called “glycodendrons” binds to the dendritic cells, preventing the HIV virus from binding.
  2. The immune system creates antibodies to this artificial block which also recognizes HIV virus.

If the glycodendrons prove to stimulate a strong enough immune system response to preemptively stimulate the body to create antibodies, the Scripps researchers will have created the first successful HIV vaccine.

So far, the treatment has induced HIV antibodies in mice, and, in laboratory studies, has been able to block the virus from infecting immune cells.

“Vaccine” for leukemia

Biology News reports that a research team at the Moores Cancer Center at University of California, San Diego (UCSD) have gotten a leukemia patient’s immune system to start attacking their leukemia cancer cells. To do this, the researchers modified cancer cells to make them more recognizable by the immune system. These immunity-recognizable cancer cells were then injected back into the patient so that their body could begin producing antibodies.

Basically: a vaccine for leukemia.

This works because the antibodies that are produced target a transmembrane receptor called ROR1, which is involved in the Wnt pathway. Normally our bodies destroy all immune cells that make antibodies that recognize self, which is anything that is naturally present in the body. However, this particular part of the Wnt pathway is only present early on in development, so all the ROR1 receptors are gone before the immune system develops.