Anthrax toxicity depends on genetic makeup
Researchers in a study posted online in the journal Proceedings of the National Academy of Sciences discovered that some people's lymphocyte cells were less likely to die than others when exposed to a mixture of the bacterium Bactillus anthracis, according to Scientific American.
The difference between the cells likely to be more affected by the bacteria and those likely to survive appears to be related to the regulation of a gene, known as capillary morphogenesis gene 2, which creates a protein membrane around lymphocyte cells. The host membrane protein is exploited by anthrax as a principal receptor and plays a key role in determining sensitivity to the toxin, according to PNAS.org.
"We already knew that infection by the same organism in different people can have very different outcomes," David Relman, the chair of the Institute of Medicine's Forum on Microbial Threats, said, Scientific American reports. "But, until now, it's been very difficult to determine whether this variability was due to genetic or environmental factors."
The scientists, led by geneticist Mikhail Martchenko from the Stanford University School of Medicine and funded by the U.S. Department of Defense, used tissue samples from more than 200 people of varying descent that were stored for the HapMap Project, a freely available public genome database.
Of those cells used for the study, the majority were overtaken by the anthrax bacterium. The cells of three people of European descent, however, required hundreds or even thousands of times more of the anthrax toxin before succumbing. Samples from people who were known to be related to one another often had similar reactions to the toxin.
"It could lead to the development of novel treatment strategies, perhaps by blocking the interaction between the toxin and the receptor or by down-regulating its expression," Relman, who was not involved in the research, said, Scientific American reports. "The findings could also provide a possible means for predicting who is likely to become seriously ill after exposure, which could be extremely useful when faced with a large number of exposed people."