The fundamental study for translingual vaccine development

大多数通用免疫程序使用针头来注射疫苗，这带来了针头重复使用引起交叉污染的风险。无需针头物理穿透的免疫接种将大大提高疫苗接种的简便性。在鼻腔和口服抗原注射中，通常使用霍乱毒素(CT)等粘膜佐剂来增强随后的免疫反应。我们提出了另一种新的疫苗接种途径：舌内免疫(舌面免疫)。我们发现，当卵蛋白(OVA)和CT应用于C57BL/6小鼠的舌面时，激发了抗原特异性的粘膜和系统免疫反应。观察到粘膜分泌物和血浆标本中OVA特异性IgA和Ig G抗体水平升高，增强的免疫力持续了整整一年。跨语言免疫还能在粘膜组织和脾组织中诱导OVA特异性的IgA和Ig G抗体形成细胞。此外，在经口免疫CT的小鼠中，口服CT攻击引起的腹泻明显受到抑制。结果表明，舌内免疫、舌下免疫、鼻内免疫和胃内免疫在预防沙门氏菌引起的腹泻方面没有太大差异，以沙门氏菌为佐剂的舌间免疫不会引起体重减轻、体温降低、发热或严重的炎症反应，也不会影响味觉。然而，在舌头肌肉注射CT的小鼠身上观察到了这些不良反应。虽然CT在舌内接种中不一定是安全的，但通过使用更安全的粘膜佐剂，舌内免疫是通过在舌面上简单地应用一种溶液来实现的，作为一种有用的、容易获得的、非侵入性的诱导疫苗免疫的方法，CT在新的粘膜途径的开发中发挥了重要作用。

Most generic immunization procedures use needles to administer vaccines, which poses the risk of cross-contamination arising from needle reuse. Immunization without physical penetration by needles would greatly increase vaccination ease. In nasal and oral antigen administration, mucosal adjuvants such as cholera toxin (CT) are commonly used to enhance subsequent immune responses. We present herein another novel route of vaccine delivery : translingual immunization (immunization via the surface of the tongue).We found that when ovalbumin (OVA) and CT applied to the tongue surface of C57BL/6 mice stimulated antigen-specific mucosal and systemic immune responses. Increased levels of OVA-specific IgA and IgG antibodies in mucosal secretions and plasma samples were observed, and the enhanced immunity persisted for a full year of observation. Translingual immunization also could induce OVA-specific IgA and IgG Ab-forming cells in the mucosal tissues and spleen. Moreover, in mice translingually immunized with CT, diarrhea induced by oral CT challenge was significantly suppressed. We demonstrated that there was no great difference in translingual, sublingual, intranasal, and intragastric immunization for prevention of CT-induced diarrhea.Translingual immunization with CT as a mucosal adjuvant did not cause weight loss, hypothermia, fervescence, or severe inflammatory response, nor did it affect taste perception. However, these adverse effects were observed in mice in which CT was intramuscularly injected into the tongue. Although use of CT might not necessarily be safe in translingual vaccination, by using much safer mucosal adjuvant, translingual immunization is achieved by simple application of a solution to the surface of the tongue, and it has been important in the development of the novel mucosal route as a useful and easily accessible, noninvasive way to induce vaccine immunity.