Use of capillary electrophoresis to select a DNA aptamer that recognizes swine anaphylatoxin C5a.

Complement factor 5a is a potent proinflammatory mediator that contributes to the pathogenesis of numerous inflammatory diseases. Protein-based C5a inhibitors have proven to be clinically valuable. Aptamers, which are oligonucleic acid chains or polypeptides, can bind to target molecules and hence have the potential to be used for detection and blockade of targets. Here, we describe the discovery that the single-stranded DNA aptamer S1 can bind specifically to swine C5a, which can then be quickly selected for with capillary electrophoresis for high-throughput sequencing. Aptamer S1 bound specifically to swine C5a with a dissociation constant of 4 μM as measured by surface plasmon resonance (SPR). Moreover, aptamer S1 inhibited C5a-induced chemotaxis of neutrophils in vitro. Our study suggests that the S1 aptamer has great potential to be a key structure in the development of effective therapeutic agents against inflammatory diseases.