Date Published: July 26, 2017
Publisher: Public Library of Science
Author(s): Rémi Barbieri, Rania Mekni, Anthony Levasseur, Eric Chabrière, Michel Signoli, Stéfan Tzortzis, Gérard Aboudharam, Michel Drancourt, David Caramelli.
Chemical decomposition and fragmentation may limit the detection of ancient host and microbial DNA while some proteins can be detected for extended periods of time. We applied paleoproteomics on 300-year-old dental pulp specimens recovered from 16 individuals in two archeological funeral sites in France, comprising one documented plague site and one documented plague-negative site. The dental pulp paleoproteome of the 16 teeth comprised 439 peptides representative of 30 proteins of human origin and 211 peptides representative of 27 proteins of non-human origin. Human proteins consisted of conjunctive tissue and blood proteins including IgA immunoglobulins. Four peptides were indicative of three presumable Yersinia pestis proteins detected in 3/8 dental pulp specimens from the plague-positive site but not in the eight dental pulp specimens collected in the plague-negative site. Paleoproteomics applied to the dental pulp is a new and innovative approach to screen ancient individuals for the detection of blood-borne pathogens and host inflammatory response.
The discovery and the characterization of microbes in ancient environmental and human specimens expanded the knowledge about the evolution of microbiota and pathogens and rose new paradigms concerning the dynamics of deadly epidemics . New insights into bacteria and archaea constituting past microbiota have been gained notably by analyzing ancient dental calculus microbiota [2–4] and digestive tract microbiota . Furthermore, an expanding knowledge of the evolution of pathogens such as Yersinia pestis [6, 7], Mycobacterium tuberculosis and Mycobacterium leprae  and variola  helped reconstitute the dynamics of past devastating epidemics caused by these pathogens.
We applied paleoproteomics to the dental pulp collected from buried individuals in order to develop a new diagnostic approach for ancient infectious diseases, using plague as an illustrative situation. Data here reported indicate that four peptides corresponding among others to Y. pestis proteins have been detected in three individuals exhumed from a documented 18th century plague site in France, while no such peptide was detected in a negative control 18th century site in France. In particular, one of these four peptides found twice in one individual yielded significant blast results only with Y. pestis and Y. pseudotuberculosis, which are undistinguishable when using this approach. In light of the historical, archeological and anthropological data from the archeological site of Le Delos  in which the presence Y. pestis was already confirmed by F1 antigen detection and suicide PCR [30, 31], we interpreted these four peptides as indicative of Y. pestis in these three individuals who died during the plague epidemic of 1720–1722.