Innate cells shown to form immunological 'memory' and protect against viral infection

(Press-News.org) Researchers have demonstrated that cells of the innate immune system are capable of "memory", and of mounting rapid protection to an otherwise lethal dose of live vaccinia virus. The study, published in the Open Access journal PLoS Pathogens on August 4th, challenges previous thought that only B cells and T cells can store memory to ward off future infection. The finding, by researchers from Beth Israel Deaconess Medical Center, Harvard Medical School, and Hebrew University and Duke University, has potentially significant consequences for the design of future vaccines, particularly for HIV.

Immunological "memory" is what the immune system builds to respond more effectively to pathogens (such as bacteria and viruses) that the host organism has encountered previously. Traditionally, immunological "memory" has been thought to reside within the cells of the adaptive arm of the immune system (B cells and T cells) that recognize highly specific portions of pathogens through unique receptors.

This study, lead by Dr. Geoffrey Gillard, shows that an innate population of cells, called natural killer (NK) cells form "memory" to vaccinia virus infection despite the fact that they lack the receptors of traditional "memory" cells. Transfer of "memory" NK cells into immunodeficient mice was enough to protect these mice against a normally lethal exposure to vaccinia virus. Because the NK cell population lacks the receptors that allow B and T cells to develop highly specific "memory" responses to pathogens, the study raises important questions to the manner in which "memory" NK cells are capable of recognizing virus upon a second exposure.

Understanding how innate "memory" functions will be critical for incorporating this property into more effective vaccines, particularly as part of a vaccine against HIV. The properties of NK memory, most notably the ability to respond very rapidly, may be helpful in exerting early control of HIV infection by limiting the ability of the virus to overwhelm the host immune system in the early stages of infection.

### FINANCIAL DISCLOSURE: This work was supported by CHAVI, grant number AI 067854. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

COMPETING INTERESTS: The authors have declared that no competing interests exist.

CITATION: Gillard GO, Bivas-Benita M, Hovav A-H, Grandpre LE, Panas MW, et al. (2011) Thy1+ Nk Cells from Vaccinia Virus-Primed Mice Confer Protection against Vaccinia Virus Challenge in the Absence of Adaptive Lymphocytes. PLoS Pathog 7(8): e1002141. doi:10.1371/journal.ppat.1002141

CONTACT:
Geoffrey Oliver Gillard
Beth Israel Deaconess Medical Center, Harvard Medical School
Boston, MA, United States
ggillard@bidmc.harvard.edu
617 447-0783

Disclaimer

This press release refers to an upcoming article in PLoS Pathogens. The release is provided the article authors and/or their institutions. Any opinions expressed in these releases or articles are the personal views of the journal staff and/or article contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the releases and articles and your use of such information.

Media Permissions

PLoS Journals publish under a Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.5/), which permits free reuse of all materials published with the article, so long as the work is cited (e.g., Kaltenbach LS et al. (2007) Huntingtin Interacting Proteins Are Genetic Modifiers of Neurodegeneration. PLoS Genet 3(5): e82. doi:10.1371/journal.pgen.0030082). No prior permission is required from the authors or publisher. For queries about the license, please contact the relative journal contact indicated here: http://www.plos.org/journals/embargopolicy.php

About PLoS Pathogens

PLoS Pathogens (www.plospathogens.org) publishes outstanding original articles that significantly advance the understanding of pathogens and how they interact with their host organisms. All works published in PLoS Pathogens are open access. Everything is immediately available subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org.