Public Release: 

Human-specific evolution in battling bugs and building babies

PLOS

Although human and chimpanzee immune systems have many identical components, this is not the case for the family of killer cell immunoglobulin-like receptors (KIR) controlling white blood cells known as natural killer (NK) cells. Published in the open-access journal PloS Genetics on November 4, a paper by Stanford University researchers describes qualitative KIR differences, acquired after humans and chimpanzees separated 6 million years ago and mainly a consequence of innovation in the human line. These differences open up an exciting avenue for explaining the differential susceptibility of humans and chimpanzees to devastating infectious diseases such as HIV/AIDS and malaria.

While immunological research has increasingly concentrated on the inbred laboratory mouse for the last half century, mice actually represent a poor model for human KIR because their NK cell receptors are so disparate from the simian primate counterparts. As a result, the researchers looked at chimpanzee KIR so that they could accurately compare them with the well-characterized human versions.

NK cells serve in both immune defense and reproduction; they contribute to early defense against infection and are implicated during the early phase of pregnancy, when uterine NK cells orchestrate enlargement of maternal arteries that will supply blood to the placenta and nourish the fetus. These vital NK cell functions seem subject to variable and competing selective pressures that have driven rapid KIR evolution and produced striking differences between humans and chimpanzees, as closely related as they are. These distinctions derive from adaptations in the human line in response to selective pressures on human NK cells due to the competing needs of defense and reproduction. Whereas chimpanzees have a potent battery of KIR that appears aimed at fighting infection, the human KIR represent a functional compromise between battling bugs and building babies.

###

FINANCIAL DISCLOSURE: This study was supported by National Institutes of Health grants AI24258 and AI22039 to Peter Parham; the authors also acknowledge the support of the Yerkes Center Base Grant RR000165. 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: Abi-Rached L, Moesta AK, Rajalingam R, Guethlein LA, Parham P (2010) Human-Specific Evolution and Adaptation Led to Major Qualitative Differences in the Variable Receptors of Human and Chimpanzee Natural Killer Cells. PLoS Genet 6(11): e1001192. doi:10.1371/journal.pgen.1001192

PLEASE ADD THIS LINK TO THE FREELY AVAILABLE ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (the link will go live when the embargo ends): http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1001192

PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plge-06-11-parham.pdf

Disclaimer

This press release refers to an upcoming article in PLoS Genetics. The release is provided by journal staff, or by the article authors and/or their institutions. Any opinions expressed in this release or article 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.

About PLoS Genetics

PLoS Genetics (http://www.plosgenetics.org) reflects the full breadth and interdisciplinary nature of genetics and genomics research by publishing outstanding original contributions in all areas of biology. All works published in PLoS Genetics are open access. Everything is immediately and freely available online throughout the world 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.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.