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. Author manuscript; available in PMC: 2014 Jun 1.
Published in final edited form as: J Immunol. 2013 Apr 24;190(11):10.4049/jimmunol.1203548. doi: 10.4049/jimmunol.1203548

FIGURE 5.

FIGURE 5

Protection of erythrocytes with PNH-induced phenotype from AP-mediated lysis. (A) In an in vitro model of PNH, acidified serum was spiked with analytes prior to co-incubation with sensitized erythrocytes. Lysis was determined by measuring absorbance at 405 nm. EDTA and PBS were used as positive and negative inhibition controls, respectively; Absorbance of erythrocytes suspended in water was used to determine maximum lysis. Plot shows a representative of three independent assays. Analytes measured at a single concentration point were analyzed as triplicates, all others in duplicates; standard deviation is shown. (B) In order to determine the influence of polyanion-targeting on inhibitory potency, the PNH assay described above was repeated with erythrocytes before and after treatment with neuraminidase to remove sialic acid from the surface. As in panel A, EDTA was used as a positive inhibitory control and absorbance of total lysis was determined in water. The pair of overlapping FH1-4 curves (FH1-4 does not contain any polyanionic host-surface recognition patch) serves as a reference for all other analytes. Plot shows a representative of two independent assays.