Egyptian versus natural mummification: tracking the differences in loss of tissue antigenicity

Previous reports of difficulties using immunohistochemical methods on mummified tissues attributed the problems mostly to the antiquity of the material. We examined mummified examples of contemporary human tissues (carotid endarterectomy specimens) obtained for research purposes, using 1) desiccation as an example of natural mummification, and 2) natron treatment (Egyptian mummification) followed by desiccation in controlled simulated desert conditions lasting up to 20 months and various reconstitution regimens. The remaining untreated tissues, fixed routinely in formalin and processed to paraffin blocks, served as a control. Additionally, we examined a contemporary human sural nerve bundle mummified in the Egyptian manner by the LIU-UMAB Mummy Project. All tissues were subjected to the same immunohistochemical procedures. There were differences in the degree of antigenicity between matching samples (desiccated only and natron treated) when comparing the same antigens. Thus, the initial mummification procedure has a crucial effect on the preservation of tissue antigenicity.