Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Immune memory from smallpox vaccination lasts more 50 years, according to Emory research

11.11.2003


Immune memory after smallpox vaccination persists for at least 50 years in immunized individuals, according to research conducted by scientists at the Emory Vaccine Center and Emory University School of Medicine. This is good news, since the findings, published in the Nov. 15 issue of the Journal of Immunology, suggest that individuals vaccinated against smallpox prior to the end of the smallpox vaccination program in 1972 may still retain at least some protection against smallpox.



Rafi Ahmed, PhD, Georgia Research Alliance Eminent Scholar and director of the Emory Vaccine Center, was principal investigator of the research study, and Shane Crotty, PhD, formerly at Emory University School of Medicine and currently a faculty member at The La Jolla Institute for Allergy and Immunology, was first author. Other members of the research team included Emory microbiologist John Glidewell, Phil Felgner, and Luis Villarreal of the University of California, Irvine, and Huw Davies of King’s College London.

Although scientists have known that acute viral infections and vaccines produce two types of long-term immune memory that provide protection against disease, they are still learning the details of these immune mechanisms.


Using a new blood test they developed to assess human antigen-specific immunity, the Emory scientists measured memory B cell responses in individuals recently vaccinated with smallpox vaccine (DryVax), in unvaccinated individuals, and in individuals vaccinated between three months and 60 years earlier. The recently vaccinated group showed a significant virus-specific memory B cell response to vaccinia, while the unvaccinated individuals were negative for vaccinia virus-specific memory B cells. Vaccinia virus-specific B cells were detected in most of the previously vaccinated individuals in the study, including those vaccinated up to 60 years after vaccination.

The scientists found that virus-specific memory B cells initially declined after smallpox immunization, but then reached a plateau approximately ten times lower than their peak, where they remained stable for more than 50 years. Although there were significantly fewer memory B cells in the most recently vaccinated group compared to those vaccinated decades earlier, there was no significant change in B cell memory between 20 and 60 years after vaccination. In addition, individuals vaccinated against smallpox maintained anti-smallpox antibodies in their blood for at least 60 years after vaccination, with no indication of decline between 1 and 60 years.

In humoral immunity, the body’s first line of defense against infection is antibodies produced by B cells, which are the primary measure of immunity for most vaccines. Memory B cells are responsible for stimulating a rapid antibody response after re-exposure to infection. In cellular immunity, activated T cells kill specific virus-infected cells and also produce cytokines –– proteins that prevent the growth of viruses and make cells resistant to viral infection. Previous studies in mice by Dr. Ahmed have shown that B cell memory can persist even without re-exposure to viral antigens, but this had not yet been demonstrated in humans.

In order to test the functionality of the memory B cells, the scientists revaccinated a group of test subjects who had been vaccinated between 22 and 48 years earlier, and detected 20-fold increases in vaccinia-virus antibodies after the second vaccination. They also tested antibody response to a specific viral protein. In previously immunized individuals they detected an antibody response prior to booster immunization as well as a strong response four weeks after booster immunization. In newly vaccinated individuals, however, the antibody response to the specific viral protein was virtually undetectable.

"The fact that there was an antibody response to this viral protein in individuals vaccinated years earlier, but no response in recently vaccinated individuals, demonstrates the potency and value of maintaining a pool of memory B cells for decades after vaccination," notes Dr. Crotty. The researchers also measured vaccinia-virus-specific T cells, and found that although the level of T cells declined gradually over time, the cells still were present even decades after immunization in most study subjects.

"Immune memory to smallpox vaccination is an excellent benchmark to help us understand the mechanisms of good vaccines and also to understand the longevity and stability of immune memory in the absence of revaccination or disease," said Dr. Ahmed. "Our findings may be useful as decisions are made about re-instituting a smallpox vaccination program. And because smallpox has an incubation period of from 12 to 14 days, this provides a window of opportunity for memory B and T cells to expand and attack the infection before the onset of clinical disease."

Dr. Crotty said, "Our findings may help assist health authorities in their decision-making process about updates or changes to the smallpox vaccination program. Our work has not shown that these people would be protected, because that cannot be directly tested, and this is an important point. But, our study does show that people maintain immune memory against smallpox for many decades, and hopefully those levels of immune memory would provide at least some amount of protection against smallpox."

Holly Korschun | EurekAlert!
Further information:
http://www.emory.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: 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...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

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

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>