Laboratoire Contrôle et Immunologie des Maladies Entériques du Nouveau-né, UR1282 Infectiologie Animale et Santé Publique, INRA de Tours, Nouzilly, France.
PLoS One. 2009 Dec 14;4(12):e8291. doi: 10.1371/journal.pone.0008291.
The development of mucosal vaccines is crucial to efficiently control infectious agents for which mucosae are the primary site of entry. Major drawbacks of these protective strategies are the lack of effective mucosal adjuvant. Synthetic oligodeoxynucleotides that contain several unmethylated cytosine-guanine dinucleotide (CpG-ODN) motifs are now recognized as promising adjuvants displaying mucosal adjuvant activity through direct activation of TLR9-expressing cells. However, little is known about the efficacy of these molecules in stimulating the intestinal immune system in neonates.
METHODOLOGY/PRINCIPAL FINDINGS: First, newborn mice received CpG-ODN orally, and the intestinal cytokine and chemokine response was measured. We observed that oral administration of CpG-ODN induces CXC and CC chemokine responses and a cellular infiltration in the intestine of neonates as detected by immunohistochemistry. We next compared the efficiency of the oral route to intraperitoneal administration in stimulating the intestinal immune responses of both adults and neonates. Neonates were more responsive to TLR9-stimulation than adults whatever the CpG-ODN administration route. Their intestinal epithelial cells (IECs) indirectly responded to TLR9 stimulation and contributed to the CXC chemokine response, whereas other TLR9-bearing cells of the lamina-propria produced CC chemokines and Th1-type cytokines. Moreover, we showed that the intestine of adult exhibited a significantly higher level of IL10 at homeostasis than neonates, which might be responsible for the unresponsiveness to TLR9-stimulation, as confirmed by our findings in IL10-deficient mice.
CONCLUSIONS/SIGNIFICANCE: This is the first report that deciphers the role played by CpG-ODN in the intestine of neonates. This work clearly demonstrates that an intraperitoneal administration of CpG-ODN is more efficient in neonates than in adults to stimulate an intestinal chemokine response due to their lower IL-10 intestinal level. In addition we report the efficiency of the oral route at inducing intestinal chemokine responses in neonate that might be taken into consideration for further vaccine development against neonatal diseases.
黏膜疫苗的发展对于有效控制以黏膜为主要入侵部位的传染病病原体至关重要。这些保护策略的主要缺点是缺乏有效的黏膜佐剂。含有多个未甲基化胞嘧啶-鸟嘌呤二核苷酸（CpG-ODN）基序的合成寡脱氧核苷酸现在被认为是有前途的佐剂，通过直接激活 TLR9 表达细胞来显示黏膜佐剂活性。然而，对于这些分子在刺激新生儿肠道免疫系统中的功效知之甚少。
方法/主要发现：首先，新生小鼠经口给予 CpG-ODN，并测量肠道细胞因子和趋化因子的反应。我们观察到，经口给予 CpG-ODN 可诱导新生小鼠肠道中 CXC 和 CC 趋化因子的反应和细胞浸润，通过免疫组织化学检测。接下来，我们比较了口服途径和腹腔内给药途径在刺激成人和新生儿肠道免疫反应方面的效率。无论 CpG-ODN 给药途径如何，新生儿对 TLR9 刺激的反应性都强于成人。他们的肠道上皮细胞（IECs）间接对 TLR9 刺激作出反应，并有助于 CXC 趋化因子的反应，而固有层中的其他 TLR9 阳性细胞则产生 CC 趋化因子和 Th1 型细胞因子。此外，我们表明，成年动物的肠道在稳态下产生的 IL10 水平明显高于新生儿，这可能是由于其对 TLR9 刺激无反应，正如我们在 IL10 缺陷型小鼠中的发现所证实的那样。
结论/意义：这是首次报道 CpG-ODN 在新生儿肠道中的作用。这项工作清楚地表明，与成人相比，腹腔内给予 CpG-ODN 更能有效地刺激新生儿的肠道趋化因子反应，因为它们的肠道 IL10 水平较低。此外，我们报告了口服途径在诱导新生儿肠道趋化因子反应方面的效率，这可能在针对新生儿疾病的进一步疫苗开发中得到考虑。
