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. 2022 Dec 28;13:1028760. doi: 10.3389/fimmu.2022.1028760

Figure 11.

Figure 11

Identification and characterisation of a dominant negative effect in an AMD -linked FI variant. (A) Fluid phase assay revealed a dominant negative effect of I340T FI upon active WT FI. Addition of 5µL of 0, 1.25, 2.5, 5, 10, 20 and 40 µg/mL I340T FI to a standard FI cofactor assay before incubation resulted in an inhibitory effect as shown by lower levels of breakdown of the C3b α’-chain when 40 µg/mL inactive FI was spiked compared to a 0 µg/mL control lane. *C1 = Control 1 (negative control including C3b, FH1-4, I340T and no WT FI. (B) I340T dominant negative effect – densitometry analysis. Licor ImageStudio™ Lite with median background subtraction was utilised to perform densitometry analysis on the SDS-PAGE gel resulting from the I340T dominant negative fluid phase assay described. Plotted are densities of C3b ⍺’ -chain remaining normalised to the beta chain for each test and normalised to the negative control (C1) value. Graph produced using GraphPad Prism V8. C1 = control 1 [C3b, FH1-4 and I340T FI only (no WT FI)].