Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New findings about protection against pneumococcal disease

31.03.2005


Findings hoped to spur the development of an improved vaccine



Since 2000, U.S. infants have been routinely immunized against pneumococcal (Streptococcus pneumoniae) infection. Now, Boston researchers have made a surprising discovery about natural immunity to pneumococcus. Two related studies, led by Dr. Richard Malley of the Children’s Hospital Boston Division of Infectious Diseases and Dr. Marc Lipsitch of the Harvard School of Public Health, suggest that natural protection from pneumococcal disease may derive from some previously unrecognized immune mechanism, which could possibly be exploited for a new vaccine. The latest study appears in the current (March 29) issue of the Proceedings of the National Academy of Sciences.

In the U.S., before the advent of the pneumococcal conjugate vaccine, known as Prevnar, S. pneumoniae caused more than 7 million ear infections each year, half a million episodes of bacterial pneumonia, and life-threatening cases of meningitis and bacteremia. Prevnar is made up of material from the outer capsule of each of the seven pneumococcal strains most common in the U.S. This material triggers recipients’ immune systems to produce so-called anticapsular antibodies specific to those strains. However, Prevnar doesn’t work against many pneumococcal strains in the developing world, where pneumococcus kills nearly 1 million children annually, and it is expensive and difficult to manufacture, leading to chronic shortages. Moreover, in several studies, use of pneumococcal conjugate vaccines caused non-vaccine strains to become more common, raising concerns that Prevnar could eventually become ineffective even in the U.S. Of 90 known pneumococcal strains, Prevnar only covers seven.


Lipsitch and Malley first conducted epidemiologic studies in unvaccinated toddlers in the U.S., Israel, and Finland. As they reported in January in the online journal PLoS Medicine, the incidence of invasive disease from almost all pneumococcal strains fell by nearly half between 1 and 2 years of age. Yet, anti-capsular antibody concentrations increased only slightly, suggesting that a mechanism other than antibody to the pathogen’s outer capsule may be conferring natural protection against pneumococcal disease.

What then might provide this protection? Looking at the first step of pneumococcal disease, colonization of the nose and throat, Malley and Lipsitch were able to elicit long-lasting immunity to pneumococcus in mice independently of any antibodies. In the current (March 29) Proceedings of the National Academy of Science, they report that when mice were exposed to live pneumococci, or to a whole-cell vaccine developed in Malley’s lab, they were highly immune to pneumococcal colonization -- even if they were genetically unable to make antibodies. Moreover, mice exposed to a single pneumococcal strain became immune not just to that strain, but to others. The immunity appeared to arise from an effect on the immune system’s CD4+ T-cells, since mice that lacked these cells did not develop immunity.

"Textbooks say that naturally-acquired protection against pneumococcal disease depends on the development of antibody against the capsule of the bacterium," says Malley, who is also an assistant professor in pediatrics at Harvard Medical School. "We were surprised to find that protection was independent of not only antibody to the capsule, but also antibody of any specificity."

Overall, their findings suggest that while antibodies are sufficient for protection against pneumococcal disease, they may not represent the natural mechanism of protection.

"An interesting observation is that HIV-infected children, whose CD4+ cells are depleted by the virus, are at about a 200-fold higher risk for pneumococcal disease," Malley adds. "Our experiments in mice may provide an explanation for that vulnerability."

The whole-cell vaccine developed by Malley’s lab could potentially protect against all pneumococcal strains, Malley says. The vaccine, made of killed pneumococcal cells, was shown to prevent colonization and invasive disease when given to animals in the form of nose drops. Malley believes the vaccine stimulates CD4+ T-cells to identify components of pneumococcus that are identical in every strain and to provide protection at the earliest stage of infection, when pneumococcus is colonizing the nasal passages.

The whole-cell vaccine, or a derivative of it, would be a boon for the developing world, because it is inexpensive, covers all pneumococcal strains, and does not require refrigeration. Malley and colleagues are now working to define precisely how the whole-cell vaccine works immunologically, and determine what parts of the killed bacterium provide the actual protection. The ultimate goal is to test the vaccine in adult volunteers, and eventually in children.

Susan Craig | EurekAlert!
Further information:
http://www.childrens.harvard.edu

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

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: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

Construction of practical quantum computers radically simplified

05.12.2016 | Information Technology

NASA's AIM observes early noctilucent ice clouds over Antarctica

05.12.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>