The life-and-death struggle between the complement system and pathogens: Mechanisms of elimination, evasion tactics, and translational potential.

The complement system, along with its intricate network, constitutes a vital component of the innate immune response, playing a pivotal role in defending the host against invading pathogens. While it is essential for maintaining immune homeostasis, dysregulation of this system can lead to significant pathological consequences: deficiencies in complement components increase susceptibility to infections, whereas excessive activation causes inflammatory tissue damage. Through its diverse functions and regulatory mechanisms, including but not limited to cytolytic effects, opsonophagocytosis, induction of inflammatory responses, and facilitation of antigen presentation, the complement system can independently or synergistically eliminate pathogens with high specificity and efficiency. In response to this robust immune defense strategy, pathogens have evolved a range of sophisticated evasion and resistance mechanisms to counteract the lethal effects of complements. In-depth research into these complement-pathogen interactions enhances our understanding of disease pathogenesis and progression, providing vital theoretical foundations and potential targets for novel therapeutics.