The enamel proteome includes a range of proteins that are well-preserved in archaeological settings but have so far received less study than those associated with sex-estimation of enamel. We look beyond sex-specific sequencing of amelogenin to investigate the potential of several serum proteins, including immunoglobulin gamma (IgG), the major immunoglobulin found in blood serum, and C-reactive protein (CRP), which is associated with inflammatory response, to provide insight into the health and stresses experienced by individuals in the past. We apply this approach to enamel samples from Mission-Period ancestral Ohlone interred at Asistencia San Pedro y San Pablo (CA-SMA-71/H; n = 11). For comparison, we also examine enamel from historic-period European-Americans interred in the City Cemetery in San Francisco (n = 12), and extracted third molars from present-day military cadets (n = 8). Results indicate that IgG is elevated among individuals at the asistencia relative to samples from present-day military cadets, and historic City Cemetery individuals (ANOVA with post-hoc Tukey Kramer tests, p < .02). Further, the inflammatory protein CRP, normally expressed at much lower levels than IgG, was present in 55% (6 of 11) of the asistencia samples, and in 17% (2 of 12) of the historic City Cemetery samples, but was not detected in enamel samples from present-day military cadets. While more studies are needed, we argue that the difference in IgG could reflect higher levels of chronic diseases such as tuberculosis among Ohlone living within the Mission system, and the presence of measurable amounts of CRP could relate to higher degrees of physical, social, and emotional stresses. To our knowledge, this is the first paleoproteomic study of immune proteins in tooth enamel. The ability to track immune responses during tooth formation could provide valuable and high-resolution information on ancient health and disease at the level of the individual over archaeological time-scales.

中文翻译：

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在牙釉质中回收的免疫蛋白作为过去人群健康的生化记录：使命时期加利福尼亚原住民的古蛋白质组学分析


牙釉质蛋白质组包括一系列在考古环境中保存完好的蛋白质，但迄今为止接受的研究少于与牙釉质性别估计相关的蛋白质。我们超越了 amelogenin 的性别特异性测序，研究了几种血清蛋白的潜力，包括血清中发现的主要免疫球蛋白 γ （IgG） 和与炎症反应相关的 C 反应蛋白 （CRP），以深入了解个人过去经历的健康和压力。我们将这种方法应用于埋葬在 Asistencia San Pedro y San Pablo （CA-SMA-71/H; n = 11） 的传教时期祖先 Ohlone 的珐琅质样本。为了进行比较，我们还检查了埋葬在旧金山城市公墓的历史时期欧洲裔美国人的牙釉质 （n = 12），并从当今的军事学员 （n = 8） 中提取了第三磨牙。结果表明，相对于来自当今军事学员和历史悠久的城市公墓个体的样本，asistencia 个体的 IgG 升高（事后 Tukey Kramer 检验的方差分析，p < .02）。此外，炎症蛋白 CRP 通常以比 IgG 低得多的水平表达，存在于 55%（11 个中的 6 个）的 asistencia 样本和 17%（12 个中的 2 个）历史悠久的城市公墓样本中，但在当今军事学员的牙釉质样本中未检测到。虽然需要更多的研究，但我们认为 IgG 的差异可能反映了生活在 Mission 系统内的 Ohlone 中更高水平的慢性病，例如肺结核，并且可测量量的 CRP 的存在可能与更高程度的身体、社会和情绪压力有关。据我们所知，这是对牙釉质中免疫蛋白的首次古蛋白质组学研究。 在牙齿形成过程中跟踪免疫反应的能力可以在考古时间尺度上提供有关个体水平古代健康和疾病的有价值和高分辨率信息。