Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
Neuroscience Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
Front Immunol. 2018 Jan 25;9:68. doi: 10.3389/fimmu.2018.00068. eCollection 2018.
A complex network of interactions exists between the immune, the olfactory, and the central nervous system (CNS). Inhalation of different fragrances can affect immunological reactions in response to an antigen but also may have effects on the CNS and cognitive activity. We performed an exploratory study of the immunomodulatory ability of a series of compounds representing each of the 10 odor categories or clusters described previously. We evaluated the impact of each particular odor on the immune response after immunization with the model antigen ovalbumin in combination with the TLR3 agonist poly I:C. We found that some odors behave as immunostimulatory agents, whereas others might be considered as potential immunosuppressant odors. Interestingly, the immunomodulatory capacity was, in some cases, strain-specific. In particular, one of the fragrances, carvone, was found to be immunostimulatory in BALB/c mice and immunosuppressive in C57BL/6J mice, facilitating or impairing viral clearance, respectively, in a model of a viral infection with a recombinant adenovirus. Importantly, inhalation of the odor improved the memory capacity in BALB/c mice in a fear-conditioning test, while it impaired this same capacity in C57BL/6J mice. The improvement in memory capacity in BALB/c was associated with higher CD3 T cell infiltration into the hippocampus and increased local expression of mRNA coding for IL-1β, TNF-α, and IL-6 cytokines. In contrast, the memory impairment in C57BL/6 was associated with a reduction in CD3 numbers and an increase in IFN-γ. These data suggest an association between the immunomodulatory capacity of smells and their impact on the cognitive functions of the animals. These results highlight the potential of studying odors as therapeutic agents for CNS-related diseases.
一个复杂的相互作用网络存在于免疫系统、嗅觉系统和中枢神经系统（CNS）之间。吸入不同的气味可以影响对抗原的免疫反应，但也可能对中枢神经系统和认知活动产生影响。我们进行了一项探索性研究，研究了一系列代表先前描述的 10 种气味类别或聚类的化合物的免疫调节能力。我们评估了每种特定气味对免疫原卵清蛋白与 TLR3 激动剂聚肌苷酸共免疫后的免疫反应的影响。我们发现，一些气味表现为免疫刺激剂，而另一些气味可能被认为是潜在的免疫抑制气味。有趣的是，免疫调节能力在某些情况下是菌株特异性的。特别是，一种名为香芹酮的香味在 BALB/c 小鼠中被发现具有免疫刺激性，而在 C57BL/6J 小鼠中则具有免疫抑制作用，分别在重组腺病毒感染的病毒清除模型中促进或损害病毒清除。重要的是，在恐惧条件反射测试中，吸入这种气味改善了 BALB/c 小鼠的记忆能力，而在 C57BL/6J 小鼠中则损害了这种能力。BALB/c 小鼠记忆能力的提高与 CD3 T 细胞向海马体的浸润增加以及编码 IL-1β、TNF-α 和 IL-6 细胞因子的 mRNA 表达增加有关。相比之下，C57BL/6 的记忆损伤与 CD3 数量的减少和 IFN-γ 的增加有关。这些数据表明气味的免疫调节能力与其对动物认知功能的影响之间存在关联。这些结果强调了研究气味作为与中枢神经系统相关疾病治疗剂的潜力。
