Complement fragment

Complement fragments" refers to the peptide products generated by proteolytic cleavage of complement proteins (e.g., C3, C4, C5) during activation of the complement system, an essential part of the innate immune response. These fragments—including C3a, C3b, C4a, C5a, and C5b—mediate diverse functions such as triggering inflammation (e.g., anaphylatoxins C3a, C5a), enhancing phagocytosis (opsonization, e.g., C3b), acting as chemoattractants for immune cells (C5a, C3a), and contributing to direct pathogen lysis via the formation of the membrane attack complex (C5b-C9)[2][3][5]. Complement dysregulation or fragment accumulation plays roles in multiple diseases, including autoimmune, inflammatory, infectious, neurological, and cancerous conditions[2][4][6]. While some therapeutics target specific activated complement fragments (notably C5 or C3), "complement fragments" as a group is not a single well-defined molecular target, but an umbrella for a heterogeneous set of cleavage products; therefore, the term is too broad and not suitable as a canonical drug target entry[2][4][5]. **Notes:** - "Complement fragments" is not a standard canonical target name but a collective term for multiple molecules produced from complement activation. - Therapeutic drugs and research typically focus on specific fragments, such as C5a or C3a, not on "complement fragments" as a whole[2][4]. - To retrieve structured and precise target information in databases or for drug discovery, it is recommended to use specific fragment names and their parent complement components (e.g., "C5a", "C3b")[2][6].

Other names

C3aC3bC4aC4bC5aC5b

Inhibition of complement cleavage/fragments (e.g., inhibiting formation of C5a, preventing MAC assembly)