The Effect of Dog-Keeping and the Intestinal Microbiota on Immune Development

早期接触宠物与降低过敏性疾病的风险有关。然而，这种联系背后的机制尚不清楚。这项研究的目的是确定养狗如何影响早期生命免疫发育，以及这种保护是否与婴儿肠道的细菌图谱有关。我们的假设是养狗改变了细菌群落的组成。 (BCC)在家中，进而影响婴儿肠道细菌含量(微生物区系)的建立。此外，养狗很可能是通过改变最终微生物区系来影响儿童早期免疫发育的，这也解释了观察到的较低的过敏风险。我们的目标是： 1)比较养狗家庭和不养宠物家庭的儿童在出生前18个月的免疫发育标志；2)比较6个月大时收集的粪便样本所反映的肠道BCC的特征；3)比较肠道微生物区系特征与出生前18个月免疫发育标志的关系。方法：一组新生儿 在怀孕期间招募母亲后，将对出生在有狗的家庭(n=60)和没有宠物的家庭(n=60)的婴儿进行评估。使用出生时、6个月和18个月大的数据点，将分析和比较养狗家庭和不养宠物家庭的儿童的相关健康结果和免疫发展的纵向轨迹模式的调查数据。免疫结果将包括总IgE水平、树突状细胞和调节性T细胞上的发育和成熟标志以及细胞因子分泌情况 对有丝分裂原、先天刺激和IgE交联抗体的反应。在18个月后，还将评估对尘螨和破伤风抗原的免疫反应以及对常见过敏原的特异性IgE水平。肠道微生物区系将通过使用PhyloChip对6个月大的粪便样本进行独立于培养的分析来表征。将对接触狗的婴儿的肠道细菌特征进行比较 以及那些来自没有宠物的家庭的人，并分析它们与健康结果和免疫发育模式的相关性。

Early life pet exposure has been associated with lowered risk of allergic disorders. However, the mechanism underlying this association is unknown. The objective of this research is to determine how dog-keeping impacts early life immune development and whether this protection is associated with the bacterial profile of an infant's intestinal tract. Our hypothesis is that dog-keeping alters the bacterial community composition (BCC) in the home and, in turn, impacts the establishment of an infant's intestinal bacterial content (microbiota). Furthermore, dog-keeping, most likely through altering the intesfinal microbiota, affects early childhood immune development in a manner that explains the observed lower risk of allergy. Our aims are: 1) To compare markers of immune development during the first 18 months of life among children living in homes that contain a dog versus those living in pet-free homes, 2) To compare characteristics of the intestinal BCC, as reflected by stool samples collected at 6 months of age, between infants living in homes that contain a dog versus those living in pet-free homes, and 3) To correlate characteristics of the intestinal microbiota to markers of immune development over the first 18 months of life. Methods: A cohort of neonates born into dog-containing (n=60) and pet-free homes (n=60) will be evaluated following maternal recruitment during pregnancy. Survey data on relevant health outcomes and longitudinal trajectory patterns of immune development will be analyzed and compared in the children from dog-containing versus pet-free homes using datapoints at birth, 6 and 18 months of life. Immune outcomes will include total IgE level, developmental and maturation markers on dendritic cells and regulatory T cells and cytokine secretion profile in response to mitogen, innate stimuli and IgE cross-linking antibody. At 18 months, immune responses to dust mite and tetanus antigen and specific IgE levels to common allergens will also be evaluated. The intestinal microbiota will be characterized by culture-independent analyses of stool samples at 6 months of age using the PhyloChip. Intestinal bacterial characteristics will be compared between dog-exposed infants and those from pet-free homes and analyzed for correlation to health outcomes and patterns of immune development.