Proteins, possibly human, found in World War II concentration camp artifact

Abstract

Museums displaying artifacts of the human struggle against oppression are often caught in their own internal struggle between presenting factual and unbiased descriptions of their collections, or relying on testament of survivors. Often this quandary is resolved in favor of what can be verified, not what is remembered. However, with improving instrumentation, methods and informatic approaches, science can help uncover evidence able to reconcile memory and facts. Following World War II, thousands of small, cement-like disks with numbers impressed on one side were found at concentration camps throughout Europe. Survivors claimed these disks were made of human cremains; museums erred on the side of caution-without documentation of the claims, was it justifiable to present them as fact? The ability to detect species relevant biological material in these disks could help resolve this question. Proteomic mass spectrometry of five disks revealed all contained proteins, including collagens and hemoglobins, suggesting they were made, at least in part, of animal remains. A new protein/informatics approach to species identification showed that while human was not always identified as the top contributor, human was the most likely explanation for one disk. To our knowledge, this is the first demonstration of protein recovery from cremains. Data are available via ProteomeXchange with identifier PXD035267.

Figure 1

Images of disks analyzed by the NYC OCME.

Figure 2

Relative ranking of species and order by peptides identified in five WWII disks. (A) ranks the disks by orders. The percent of spectra below the dotted lines represent peptides shared between all orders in a given disk. (B)–(F) X-axes identify all peptides found in a particular disk as well as the number of times that peptide was independently detected. (Sequences for (F) may be found in Supplementary Table 3) Y-axes indicates possible species assignments using different combinations of the identified peptides. Percentages reflect the number of peptides used for a species assignment as a total of all peptides identified (only species that explained > 50% of the data are shown). Only in the North Carolina disk (B) is human the most likely species interpretation (65% of peptide, tied with polar bear*). The only other disk with human specific peptides is Yad Vashem disk 5910 where human represents the third largest number of peptides (60%, again tied with polar bear), while sheep/goat (93%) and cow/deer (87%) are higher. *Identification of non-European wildlife, e.g. polar bear, Virginia white-tailed deer, alpaca, etc. are likely due to limitations of databases for the European species of these genera. For example, both polar bears (Ursus maritimus) and Eurasian brown bears (Ursus arctos arctos) are of the same genus.

Figure 3

Comparison of North Carolina hemoglobin peptide VGAHAGEYGAEALER spectrum with ²H labeled synthetic peptide. Spectral comparison between human hemoglobin peptide VGAHAGEYGAEALER (shared with Pan paniscus (bonobo) a close primate relative of humans) identified in the North Carolina disk, and its synthetic counterpart with matching b and y ions.