Effects of oral tolerance in allergen-induced airway responses

免疫前口服可溶性抗原可诱导外周免疫耐受，并有效抑制自身免疫性疾病的动物模型。然而，很少有研究集中于对Th-2型疾病的影响。小鼠对卵白蛋白(OVA)致敏，然后通过呼吸道用OVA激发，引发呼吸道高反应性(AHR)和呼吸道炎症。在免疫应答的不同阶段评价卵清蛋白的饲喂效果。在OVA致敏之前，多次高剂量喂养和多次低剂量喂养的小鼠均未出现AHR或呼吸道炎症。OVA致敏后但激发前给予高剂量OVA也可抑制AHR，部分抑制气道炎症；低剂量给予部分抑制AHR，但不影响气道炎症的发展。高剂量而不是低剂量喂养对AHR是有效的，即使在OVA激发后也是如此。这些数据表明，反应的剂量和阶段可能是决定诱导口服耐受对过敏原诱导的AHR和呼吸道炎症的影响的关键。

Oral administration of soluble antigen before immunization induces peripheral tolerance and is effective in suppressing animal models of autoimmune diseases. However, few studies have focused on effects on Th-2 type diseases. Mice were sensitized to ovalbumin(OVA) and subsequently challenged with OVA via the airways, eliciting airway hyperresponsiveness(AHR) and airway inflammation. The feeding effects of OVA at different phases of the immune response were evaluated. Mice exposed to both multiple high dose feeding and multiple low dose feeding before sensitization with OVA failed to develop AHR or airway inflammation. High dose feeding of OVA also abrogated AHR and partially suppressed airway inflammation when initiated after sensitization with OVA, but prior to challenge ; low dose feeding partially suppressed AHR but did not affect the development of airway inflammation. High dose but not low dose feeding was effective on AHR when initiated even after challenge with OVA. These data indicate that the dose and phase of the response may be critical in dictating the effect of inducing oral tolerance on allergen-induced AHR and airway inflammation