Brain-Body Institute and Department of Medicine, McMaster University, Hamilton, ON, Canada.
Chest. 2011 Apr;139(4):901-908. doi: 10.1378/chest.10-1861.
Increasing awareness of the role of intestinal commensal bacteria in the development and modulation of the immune system has led to great interest in the therapeutic potential of probiotics and other bacteria-based strategies for a range of immune-related disorders. Studies in animal models have identified strong immunomodulatory effects of many nonpathogenic bacteria and provided evidence that intestinal microbes can activate a common mucosal immune response and, thus, influence sites distant to the intestine, including the respiratory tract. Respiratory effects of probiotics in animal models have included attenuating allergic airway responses and protecting against respiratory pathogens. Dendritic cells appear central to directing the beneficial immune response to probiotic bacteria and in translating microbial signals from the innate to the adaptive immune system, whereas regulatory T cells are emerging as potentially key effectors of probiotic-mediated responses, particularly in the reduction of allergic inflammation. Despite progress in basic research, clinical trials of probiotics in allergy/asthma and respiratory infection have been highly variable at best, leading to an undermining of confidence in this potential therapeutic strategy. It is clear that there is still much to learn regarding the determinants of the diverse immune responses elicited by different bacterial strains. A deeper knowledge of the interactions between administered probiotics and the existing microbiota, together with an understanding of how the dialogue between microbes and the innate immune system is translated into beneficial/protective responses, will be required before we can achieve clinically effective bacteria-based strategies that maintain and promote respiratory health.
提高对肠道共生菌在免疫系统发育和调节中的作用的认识，使人们对益生菌和其他基于细菌的策略在一系列与免疫相关的疾病中的治疗潜力产生了极大的兴趣。动物模型的研究已经确定了许多非致病性细菌具有很强的免疫调节作用，并提供了证据表明肠道微生物可以激活共同的黏膜免疫反应，从而影响远离肠道的部位，包括呼吸道。益生菌在动物模型中的呼吸道作用包括减轻过敏气道反应和预防呼吸道病原体。树突状细胞似乎在指导益生菌细菌的有益免疫反应方面起着核心作用，并将微生物信号从先天免疫系统转化为适应性免疫系统，而调节性 T 细胞作为益生菌介导反应的潜在关键效应物正在出现，特别是在减轻过敏炎症方面。尽管基础研究取得了进展，但益生菌在过敏/哮喘和呼吸道感染中的临床试验充其量也只是高度可变的，这导致人们对这种潜在治疗策略的信心受到削弱。很明显，关于不同细菌菌株引起的不同免疫反应的决定因素，我们还有很多需要学习。在我们能够实现基于细菌的临床有效策略之前，需要更深入地了解管理益生菌与现有微生物群之间的相互作用，以及了解微生物与先天免疫系统之间的对话如何转化为有益/保护反应。
