BSE expert Professor of Immunology Alan Ebringer of King's College, London suggested that BSE might not be due to brain proteins called prions, but to an auto-immune disease where the cow's immune system is reacting to a common soil bacterium called Acinetobacter calcoaceticus. His crucial finding was that most cows with BSE had high levels of antibodies capable of attacking both Acinetobacter and their own brain cells, whilst BSE-free cows had few such antibodies. He saw this as powerful evidence that exposure to the bacterium was what caused BSE ("Prions are not infectious particles (but) the breakdown products of damaged nervous tissue".) and suggested that, after a cow has repelled an Acinetobacter invasion, the antibodies carried on working, mistakenly identifying brain cells as bacteria because of the similar protein sequences.

Alan used these observations to develop a test for BSE which was able to differentiate accurately between cows with or free from BSE, but has so far won little support or funding from the UK medical establishment to test the BSE-Acinetobacter hypothesis. Luckily, there is more interest in the US, where scientists at the University of Miami are attempting to replicate his findings.

A second paper described how Acinetobacter might be responsible for multiple sclerosis and CJD, the human form of BSE. Alan claimed that patients with MS made more antibodies than healthy people to the Acinetobacter bacteria which lurk (for instance) under people's fingernails. "What makes the bug so unusual," says Ebringer, "is that it has biochemical markers on its surface which match those on brain and nerve cells from humans, cows and other animals." The result, he believes, is that antibodies mistake brain and nerve tissue for bacteria and home in on it, causing BSE in cows, and nvCJD and MS in humans. Working with MS investigators at London's Institute of Neurology, Alan screened blood from 26 patients with MS, 20 patients with severe brain injuries caused by accidents, 10 with viral encephalitis and 25 healthy volunteers. [1] The tests showed that the MS patients made many more antibodies to Acinetobacter than the other subjects. This fits with what he found in cows with BSE.