Toll-like receptors (TLRs) are key sensors that recognize the pathogen-associated molecular patterns (PAMPs) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to activate innate immune response to clear the invading virus. However, dysregulated immune responses may elicit the overproduction of proinflammatory cytokines and chemokines, resulting in the enhancement of immune-mediated pathology. Therefore, a proper understanding of the interaction between SARS-CoV-2 and TLR-induced immune responses is very important for the development of effective preventive and therapeutic strategies. In this review, we discuss the recognition of SARS-CoV-2 components by TLRs and the downstream signaling pathways that are activated, as well as the dual role of TLRs in regulating antiviral effects and excessive inflammatory responses in patients with coronavirus disease 2019 (COVID-19). In addition, this article describes recent progress in the development of TLR immunomodulators including the agonists and antagonists, as vaccine adjuvants or agents used to treat hyperinflammatory responses during SARS-CoV-2 infection.

Toll 样受体 (TLR) 是识别严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 的病原体相关分子模式 (PAMP) 以激活先天免疫反应以清除入侵病毒的关键传感器。然而，失调的免疫反应可能会引起促炎细胞因子和趋化因子的过度产生，从而导致免疫介导的病理学增强。因此，正确理解 SARS-CoV-2 与 TLR 诱导的免疫反应之间的相互作用对于制定有效的预防和治疗策略非常重要。在这篇综述中，我们讨论了 TLR 对 SARS-CoV-2 成分的识别以及被激活的下游信号通路，以及 TLR 在调节 2019 年冠状病毒病 (COVID-19) 患者的抗病毒作用和过度炎症反应方面的双重作用。此外，本文还介绍了 TLR 免疫调节剂（包括激动剂和拮抗剂）开发的最新进展，作为疫苗佐剂或用于治疗 SARS-CoV-2 感染期间的过度炎症反应的药物。