Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel vaccine approach stimulates protective immunity against listeria

21.03.2006


Could also protect against other intracellular bacterial pathogens



When bacterial pathogens attack the surface of a cell, vaccine-induced antibodies can mount a formidable defense and fend off the bad bugs. The trouble comes when antibodies cannot recognize the pathogen because the bacteria have infected the cell and are hidden, growing inside the cell’s wall.

To mount a defense against these cloaked attackers, Darren Higgins, Associate Professor of Microbiology at Harvard Medical School, and H.G. Archie Bouwer, Immunology Research Scientist at the Earle A. Chiles Research Institute and Portland VA Medical Center, have developed a vaccine strategy for generating an attenuated strain of an intracellular bacterial pathogen. The study appears in the PNAS online early edition the week of March 20, 2006. The vaccine approach could also protect against other intracellular bacterial pathogens, such as tularemia.


The team has initially applied their strategy to Listeria monocytogenes, which affects the most vulnerable humans – the chronically ill, the elderly, pregnant women, and young children, who are susceptible to a serious infection caused by eating food contaminated with the bacteria. In the United States, an estimated 2,500 persons become seriously ill with the infection each year. Of these, 500 die.

After absorption by antigen presenting cells, the attenuated Listeria strain does not replicate, and is readily killed. Unlike other attenuated Listeria strains that do not replicate in host cells, vaccine studies in animals showed that the new strain provided protection from challenge with a virulent, disease-causing, Listeria strain.

"For the first time, an attenuated strain of Listeria that does not replicate in an animal and does not require any manipulation of the bacterium or host prior to immunization still provides protective immunity," Higgins said.

The team found the replication-deficient vaccine strain of Listeria was cleared rapidly in both normal and immunocompromised mice. At the same time, a required class of T-cells – coordinators of the immune system – was stimulated following immunization. As a result, animals immunized with the vaccine strain were resistant to 40 times the lethal dose of virulent Listeria.

"In theory, we could apply this vaccine strategy to other bacterial pathogens like Salmonella," said Higgins. "All we need is to use existing strains that do not replicate inside host cells."

The new Listeria vaccine was based on a 2002 study performed by the Higgins group in which they developed killed E. coli strains as vehicles for delivering antigens to professional antigen presenting cells in the body. In the prior study, Higgins showed that the E. coli-based vaccines protected mice from developing tumors when challenged with melanoma producing cells.

"We have now taken our E. coli-based cancer vaccine work and expanded it into infectious disease areas," Higgins said. "Our Listeria studies demonstrate the potential to generate vaccine strains of bacteria that are effective, yet safe for both healthy and immunocompromised individuals."

The Higgins and Bouwer team is continuing to improve and expand their approach to other intracellular bacteria.

Judith Montminy | EurekAlert!
Further information:
http://www.hms.harvard.edu

More articles from Health and Medicine:

nachricht One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center

nachricht The gut microbiota plays a key role in treatment with classic diabetes medication
01.06.2017 | University of Gothenburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>