The International Egyptian Mummy Tissue Bank

The International Egyptian Mummy Tissue Bank

In order to obtain sufficient quantities of samples from different mummies to enable the schistosomiasis study to be undertaken, the Egyptian Mummy Tissue Bank was established at the Manchester Museum, University of Manchester. The aim was to collect and store samples from Egyptian mummies held in collections outside Egypt in order to provide the world’s first international resource for preserving and researching ancient tissue.

The Manchester Museum approached more than 8,000 institutions worldwide (museums, medical institutions, and so forth) to ascertain if they held mummies in their collections and would be willing to provide milligram samples for the bank.

This international search and call for participation have resulted in the collection of many samples from mummies of different periods and social groups. These are being used in studies on schistosomiasis, and they also provide material for researchers and specialists in many disciplines to study the occurrence and patterns of various other diseases.

Thus, the tissue bank is able to make a unique contribution to investigations relating to the history of disease.

Once the Egyptian Mummy Tissue Bank was established, the Manchester researchers set out to develop an immunological diagnostic tool that could be applied to large numbers of small samples.

Some already-existing procedures were very expensive, low in sensitivity, and often required body fluid and therefore would have been impractical for the bank’s ancient, dehydrated tissue samples. Eventually, immunocytochemistry was selected and has been successfully applied in the project to both ancient and modern tissues.

Whereas in living tissue, the simplest way to detect the presence of a disease is to look for its antibody (the human body custom-designs these molecules to fight off different diseases), it is unlikely that antibodies survive well in ancient tissue. Immunocytochemistry, however, had the potential to work well in detecting schistosomi-asis in the bank’s ancient tissue because it could detect the presence of any remaining antigen that was part of either the schistosome worm or the egg that originally caused the disease.

First, a special antiserum for the schisto-some parasite had to be developed. The antiserum would contain antibodies that, if the antigen were present in the tissue as either a dead or living form of the parasite, would bind to specific antigen sites called epitopes.

Essentially, the antibodies would track down the particular antigen still present in the tissue if the person had ever suffered from the disease. A simultaneous process, tissue staining, would introduce new trackers—molecular tags that would bind with a specific antibody.

Depending on the tag chosen, this would show up under the microscope in one of several colors.

Using these methods, the Manchester research team was indeed able to visualize positive staining to S. mansoni and S. haematobium antigens, first in modern mouse tissue and then in a tissue sample taken from an Egyptian cadaver some fifty years ago, indicating the presence of schistosomiasis in these examples. The tech-niques were next applied to ancient tissues, and again positive immunostaining was achieved, demonstrating that schistosome antigens could survive for thousands of years.

Immunocytochemistry has added a new and effective method of diagnosing not only schisto-somiasis but also other diseases in ancient tissue.

Follow-up studies undertaken at Manchester have employed ELISA and DNA to confirm the immunocytochemistry results obtained on the ancient tissue samples. Further research at Manchester has also led to the identification of parasite DNA in one of the samples.

These studies may ultimately enable scientists to study and compare the genetic evolution and development of the schistosome over several thousand years, and in turn, this may inform some of the genetically based preventative measures now being developed to combat the disease. It will be of considerable interest to see how this pathogen has so successfully developed its survival strategies in order to evade destruction by the human immune system.