Faculty of Medicine, University of British Columbia, Vancouver, Canada.
Faculty of Medicine, University of British Columbia, Vancouver, Canada; Division of Infectious Disease, University of British Columbia, Vancouver, Canada; Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
Immunobiology. 2021 Jan;226(1):152052. doi: 10.1016/j.imbio.2020.152052. Epub 2020 Dec 24.
The century-old tuberculosis vaccine BCG has been the focus of renewed interest due to its well-documented ability to protect against various non-TB pathogens. Much of these broad spectrum protective effects are attributed to trained immunity, the epigenetic and metabolic reprogramming of innate immune cells. As BCG vaccine is safe, cheap, widely available, amendable to use as a recombinant vector, and immunogenic, it has immense potential for use as an immunotherapeutic agent for various conditions including autoimmune, allergic, neurodegenerative, and neoplastic diseases as well as a preventive measure against infectious agents. Of particular interest is the use of BCG vaccination to counteract the increasing prevalence of autoimmune and allergic conditions in industrialized countries attributable to reduced infectious burden as described by the 'hygiene hypothesis.' Furthermore, BCG vaccination has been proposed as a potential therapy to mitigate spread and disease burden of COVID-19 as a bridge to development of a specific vaccine and recombinant BCG expression vectors may prove useful for the introduction of SARS-CoV-2 antigens (rBCG-SARS-CoV-2) to induce long-term immunity. Understanding the immunomodulatory effects of BCG vaccine in these disease contexts is therefore critical. To that end, we review here BCG-induced immunomodulation focusing specifically on BCG-induced trained immunity and how it relates to the 'hygiene hypothesis' and COVID-19.
由于卡介苗（BCG）有预防各种非结核病原体的良好记录，这种具有百年历史的结核病疫苗重新引起了人们的兴趣。这种广谱保护作用很大程度上归因于训练有素的免疫，即固有免疫细胞的表观遗传和代谢重编程。由于 BCG 疫苗安全、廉价、广泛可用、可作为重组载体使用且具有免疫原性，因此它具有巨大的潜力，可以作为各种疾病（包括自身免疫、过敏、神经退行性和肿瘤疾病）的免疫治疗剂，以及预防传染病的措施。特别值得关注的是，卡介苗接种被用于对抗在工业化国家中日益普遍的自身免疫和过敏疾病，这归因于如“卫生假说”所述的传染性负担的减少。此外，卡介苗接种已被提议作为一种潜在的治疗方法，以减轻 COVID-19 的传播和疾病负担，作为开发特定疫苗的桥梁，并且重组 BCG 表达载体可能对引入 SARS-CoV-2 抗原（rBCG-SARS-CoV-2）以诱导长期免疫有用。因此，了解 BCG 疫苗在这些疾病中的免疫调节作用至关重要。为此，我们在这里回顾了 BCG 诱导的免疫调节作用，特别是 BCG 诱导的训练有素的免疫以及它与“卫生假说”和 COVID-19 的关系。
