Abstract:Complement system is a major component of innate immune system, which provides a vital first-line barrier to invading pathogens. The dysfunction of human complement system is related to multiple diseases, such as rheumatoid arthritis, autoimmune hemolytic anemia, and COVID-19. At the moment, most of the clinical complement inhibitors are chemically synthesized, which show poor selectivity and result in decreased immunity after long-term use. In contrast, natural anti-complement agents feature low toxicity and ease of being absorbed. Particularly, anti-complement agents of microbial origin have unique advantages and application potential, which can be discovered and identified by genome mining and produced in large quantities after metabolic engineering and fermentation optimization. However, related research is still in its infancy. Here we summarized the clinical applications of common complement inhibitors in recent years and reviewed the research and development of anti-complement agents of microbial origin, hoping to provide a reference for the clinical research on complement inhibitors and development of natural anti-complement agents.