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Fig. 1 Detection of anti-properdin autoantibodies: A.Levels of anti-properdin in 74 patients with LN and 72 healthy volunteers. B. Dose dependent ELISA with anti-properdin positive patients. C. SPR senzograms of binding of purified IgG from seropositive patient 33 (P33), D. - from seropositive patient 35 (P35) and E. - from seropositive patient 38 (P38) to properdin. F. SPR senzograms of binding of purified IgG from healthy volunteer (K1) and G. - from healthy volunteer (K2) to properdin.
Fig 2. Statistical analysis with anti-properdin autoantibodies: A. Levels of anti-properdin autoantibodies in patients divided on the complex clinical-laboratory estimation for LN activity according BILAG Renal Score. B. Comparative analysis of proteinuria in anti-properdin positive and anti-properdin negative patients in cross-section analysis. C. Correlation between levels of anti-properdin antibodies and eGFR. D. Levels of anti-properdin in patients with LN depending on the presence or absence of pathological ANA, E. anti-dsDNA, F. C3 hypocomplementemia, G. C4 hypocomplementemia and H.anti-C1q. With ”+” is marked the presence of increased ANA, anti-dsDNA and anti-C1q; with ”-” are marked the reference values of ANA, anti-dsDNA and anti-C1q in the samples. The two groups in every graphic were compared via Mann-Whitney, nonparametric t-test. I.Correlation between levels of anti-properdin and levels of ANA,J. anti-dsDNA, K. C3, L. C4 and M.anti-C1q in patients with LN. In order to estimate the correlations between anti-properdin with every immunological markers a nonparametric Spearman analysis was used.
Fig. 3. Functional analysis with anti-properdin autoantibodies: A. SPR sensograms for the effect of purified IgG from patient 33 (P33), positive for anti-properdin antibodies and from healthy volunteer (К1) on properdin binding with C3b, B. with C3b+FB (proconvertase),C. and with C3b+FB+FD (convertase) in real time. D.The effect of purified IgG from patient 35 (P35), positive for anti-properdin and from healthy volunteer (К1) on properdin binding with C3b, E. with C3b+FB (proconvertase), F. and with C3b+FB+FD (convertase) in real time. G. The effect of purified IgG from patient 38 (P38), positive for anti-properdin and from healthy volunteer (К1) on properdin binding with C3b, H. with C3b+FB (proconvertase), I. and with C3b+FB+FD (convertase) in real time. Properdin is immobilized on SPR chip and then expose to IgG from patients positive for anti-properdin (P33, P35 and P38) and IgG from healthy volunteer (К1), followed by C3b (A., D., G. ), C3b+FB (B., E., H. ) and C3b+FB+FD (C., F., I. ) addition.J. Histogram of FACS analysis of С3 deposition in the presence of purified IgG from patients 9 (P9) and K. - purified IgG from patients 35 (P35), both positive for anti-properdin. L.Histogram of FACS analysis of С3 deposition in the presence of purified IgG from patients 32 (P32) and M. - purified IgG from patients 17 (P17), both positive for anti-C3. All patients are compared with a control sample (К85).
Fig. 4 Prediction of the B cell epitopes of properdin: A.Epitopes, predicted by the IEDB server http://tools.iedb.org/bcell/.B. Visualizaiton of the predicted peptides (red) on the surface of a properdin monomer (green)