Public release date: 23-Aug-2007

Human immune proteins crucial for fighting cancer, viruses and bacterial infections belong to an ancient and lethal toxin family previously only found in bacteria, Australian researchers have found.

These proteins, called perforins, are related to bacterial toxins that cause diseases such as anthrax, gas gangrene and scarlet fever. The discovery was made by a team led by Professor James Whisstock and Dr Michelle Dunstone from Monash University’s School of Biomedical Sciences.

Professor Whisstock, winner of the 2006 Science Minister’s Prize for Life Scientist of the Year, said the team was stunned when it became clear that the bacterial toxins and perforins had a common ancestor.

“Over millions of years of evolution bacteria developed these proteins as weapons of attack,” he said. “But animals have evolved these proteins for defence against that attack. It’s a molecular arms race and there’s still no clear winner.”

Professor Whisstock said perforins were so-called because they kill bacteria, virally-infected cells and cancerous cells by punching tiny holes that perforate them. “People who lack one of these perforins can develop a serious blood disease called hemophagocytic lymphohistiocytosis and may be predisposed to develop cancer,” he said.

Professor Whisstock said certain perforins were not only important for defending humans against attack by bacteria and viruses, but also important for propagating the human species because of their role in embryo implantation. “It is ironic that we fear diseases such as anthrax yet from the same family of toxins comes a protein that is involved in reproduction,” he said.

Ralph’s Note- This is important due to anthrax vaccination. Those vaccinated should be monitored for abnormally low performing levels now. This Vaccination can now lead to unanticipated consequences