Barnum Scott R
Departments of Microbiology and Neurobiology, University of Alabama at Birmingham, Birmingham, Ala., USA.
J Innate Immun. 2015;7(4):333-9. doi: 10.1159/000371423. Epub 2015 Feb 6.
Activation of complement leads to generation of the 3 anaphylatoxins C3a, C4a, and C5a. Although all 3 peptides are structurally similar, only C3a and C5a share a similar functional profile that includes the classic inflammatory activities and, more recently, developmental homing and regenerative properties among others. In contrast, the functional profile of C4a is questionable in most cases owing to contamination of C4a preparations with physiologically relevant levels of C3a and/or C5a. Combined with the absence of an identified C4a receptor and the inability of C4a to signal through the C3a and C5a receptors, it is clear that C4a should not be included in the family of complement anaphylatoxins.
补体激活会导致产生三种过敏毒素C3a、C4a和C5a。尽管这三种肽在结构上相似，但只有C3a和C5a具有相似的功能特征，包括典型的炎症活性，以及最近发现的发育归巢和再生特性等。相比之下，在大多数情况下，由于C4a制剂中含有生理相关水平的C3a和/或C5a而受到污染，C4a的功能特征存在疑问。再加上未发现C4a受体，且C4a无法通过C3a和C5a受体发出信号，显然C4a不应被纳入补体过敏毒素家族。
