Fig. 4
ARMS2 functions as complement activator on the cell surface. a C3b deposition on CHO-K1 cells is enhanced after incubation for 45 min in 20% NHS preincubated with ARMS2 (100–750 nM) (n = 4, **p = 0.0021, 100 nM versus 750 nM). Human serum albumin (HSA) had no and factor H an inhibiting effect on C3b deposition. C3b deposition on cells in NHS alone was set as 100%. b C3b deposition on CHOpgsA cells is not enhanced after incubation in 20% NHS with ARMS2, factor H or HSA (each 100–750 nM) (each n = 3). C3b deposition on cells in NHS alone was set as 100%. c Deposition of C3b is increased on ARMS2 (100–750 nM) coated CHO-K1 cells (n = 4, **p = 0.0021) after incubation in 20% NHS. HSA or factor H does not enhance C3b binding. d ARMS2 (500 nM) attached to CHO-K1 cells and incubated for 45 min in 20% NHS enhanced C3b deposition over time as compared to cells alone in 20% NHS (latter was set as 100%). Error bars show median MFI values ± s.d. (n = 3, **p = 0.0011, NHS versus NHS + ARMS2). e ARMS2 (100–750 nM) added to 20% NHS without cells did not enhance Ba generation, as determined by ELISA. Data represent mean values ± s.d. (n = 3). f Deposition of C3b on ARMS2 (100–750 nM) coated CHO-K1 cells is enhanced in 20% complement active NHS incubated for 45 min but not in heat inactived NHS (30 min, 56 °C). Data represent median MFI values ± s.d. in % (NHS alone was set as 100%) (n = 3, **p = 0.0014, NHS versus hiHS at 750 nM ARMS2)