Complement activation by PVA as measured by ELIFA (enzyme-linked immunoflow assay) for SC5b-9

Polyvinyl alcohol (PVA) coated onto polyethylene (PE) tubes exposed to human serum for 1 hour at 37°C resulted in the production of 1.03±0.04 μg/cm2 of the soluble form of the terminal membrane attack complex, SC5b-9. This was approximately 20× that produced by the polyethylene. About one quarter of this total was found associated with the surface of PVA. SC5b-9 concentrations were determined by enzyme-linked immunoflow assay (ELIFA) a variant on ELISA that involved drawing the test sample, the antibodies and the chromogenic reagent through a nitrocellulose membrane filter. ELIFA enabled analysis of protein concentrations in the presence of SDS, so that SDS (0.05%) was used to desorb adsorbed SC5b-9 prior to analysis together with SC5b-9 in the bulk to get a more complete picture of PVA-associated complement activation.