Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
Yili Innovation Center Europe B.V., Wageningen, Netherlands.
Front Immunol. 2020 Jan 9;10:2976. doi: 10.3389/fimmu.2019.02976. eCollection 2019.
Pregnancy is associated with adaptations of the immune response and with changes in the gutmicrobiota. We hypothesized the gut microbiota are involved in inducing (part of) the immunological adaptations during pregnancy. To test this hypothesis, we collected feces from pregnant conventional mice before and during pregnancy (days 7, 14, and 18) and microbiota were measured using 16S RNA sequencing. At day 18, mice were sacrificed and splenic (various Th cell populations) and blood immune cells (monocyte subsets) were measured by flow cytometry. The data were compared with splenic and blood immune cell populations from pregnant (day 18) germfree mice and non-pregnant conventional and germfree mice. Finally, the abundances of the individual gut bacteria in the microbiota of each conventional pregnant mouse were correlated to the parameters of the immune response of the same mouse. The microbiota of conventional mice were significantly different at the end of pregnancy (day 18) as compared with pre-pregnancy (Permanova, < 0.05). The Shannon index was decreased and the Firmicutes/Bacteroidetes ratio was increased (Friedman followed by Dunn's test, < 0.05), while abundances of various species (such as , and were significantly different at day 18 compared with pre-pregnancy. In pregnant conventional mice, the percentage of Th1 cells was decreased, while the percentages of Treg cells and Th2 cells were or tended to be increased vs. non-pregnant mice. In germfree mice, only the percentage of Th1 cells was decreased in pregnant vs. non-pregnant mice, with no effect of pregnancy on Treg and Th2 cells. The percentages of monocyte subsets were affected by pregnancy similarly in conventional and germfree mice. However, the activation status of monocytes (expression of CD80 and MHCII) was affected by pregnancy mainly in conventional mice, and not in germfree mice. Correlation (Spearman's coefficient) of pregnancy affected microbiota with pregnancy affected immune cells, i.e., immune cells that were only affected differently in conventional mice and germfree mice, showed 4 clusters of bacteria and 4 clusters of immune cells, some of these clusters were correlated with each other. For instance, the microbiota in cluster 1 and 2 (in which there were various short chain fatty acid producing microbiota) are positively correlated with immune cells in cluster B, containing Treg cells and Th2 cells. Microbiota and immune cells are affected by pregnancy in mice. The different immunological adaptations to pregnancy between conventional and germfree mice, such as the increase in Treg and tendency to an increase in Th2 cells in conventional pregnant mice only, may suggest that the microbiota may play a role in adapting the maternal immune response to pregnancy.
妊娠与免疫反应的适应性改变和肠道微生物群的变化有关。我们假设肠道微生物群参与诱导妊娠期间（部分）免疫适应性改变。为了验证这一假设，我们在妊娠前（第 7、14 和 18 天）和妊娠期间（第 18 天）从常规妊娠小鼠中收集粪便，并使用 16S RNA 测序测量微生物群。在第 18 天，处死小鼠，通过流式细胞术测量脾（各种 Th 细胞群）和血液免疫细胞（单核细胞亚群）。将这些数据与妊娠（第 18 天）无菌和非妊娠常规和无菌小鼠的脾和血液免疫细胞群进行比较。最后，将每个常规妊娠小鼠的肠道细菌的丰度与同一小鼠的免疫反应参数相关联。与妊娠前相比，常规妊娠小鼠的微生物群在妊娠末期（第 18 天）明显不同（Permanova，<0.05）。Shannon 指数降低，厚壁菌门/拟杆菌门比值增加（Friedman 随后进行 Dunn 检验，<0.05），而各种物种的丰度（如 、 和 ）在第 18 天与妊娠前相比有显著差异。在妊娠常规小鼠中，Th1 细胞的百分比降低，而 Treg 细胞和 Th2 细胞的百分比增加或倾向于增加，与非妊娠小鼠相比。在无菌小鼠中，与非妊娠小鼠相比，只有妊娠时 Th1 细胞的百分比降低，而妊娠对 Treg 和 Th2 细胞没有影响。妊娠对常规和无菌小鼠中单核细胞亚群的影响相似。然而，单核细胞的激活状态（CD80 和 MHCII 的表达）主要受常规小鼠妊娠的影响，而不受无菌小鼠妊娠的影响。与妊娠相关的微生物群与与妊娠相关的免疫细胞之间的相关性（Spearman 系数），即仅在常规小鼠和无菌小鼠中不同受妊娠影响的免疫细胞，显示出 4 个细菌群和 4 个免疫细胞群，其中一些群与彼此相关。例如，群 1 和 2 中的微生物群（其中含有各种短链脂肪酸产生的微生物群）与群 B 中的免疫细胞呈正相关，群 B 包含 Treg 细胞和 Th2 细胞。微生物群和免疫细胞在怀孕的小鼠中受到影响。常规和无菌小鼠之间对妊娠的不同免疫适应性，例如常规妊娠小鼠中 Treg 和 Th2 细胞增加的趋势，可能表明微生物群可能在适应母体对妊娠的免疫反应方面发挥作用。
