Development of a C3c-based ELISA method for the determination of anti-complementary potency of Bupleurum polysaccharides

Traditionally, determination of inhibitory potency of complement inhibitors is performed by the hemolytic assay. However, this assay is not applicable to the lectin pathway, thus impeding the understanding of complement inhibitors against the overall function of the complement system. The main objective of our study was to develop a specific enzyme-linked immunosoihent assay (ELISA) as an alternative method to assess the anti-complement activity, particularly against the lectin pathway. By using respective coating substrates against different activation pathways, followed by capturing the stable C3c fragments, our ELBA method can be used to screen complement inhibitors against the classical pathway and the lectin pathway. The inhibitory effect of sununin on the classical pathway, as measured by our hemolytic assay is consistent with previous reports. Further assessment of suramin and Bupleurum polysaccharides against the lectin pathway showed a good reproducibility of the method. Comparison of the lectin pathway IC5is between Ruplearum.smithii var, purviPliam polysaccharides (1.055 ingtmE) and Buplcurann chinense polysaccharides (0.98 ing/mL) showed that similar to the classical and alterative pathway, these two Bupleurum polysaccharides had comparable anti complementary properties against the lectin pathway. The results demonstrate that the described EIASA assay can compensate for he shortcomings of the hemolytic assay in lectin pathway. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).