Fig. 2
Aβ induces MAC deposition on RPE in vitro. a Western blot of fibrillar Aβ1–40 preparation from six sampling time points. A general increase of high-molecular weight, fibrillar Aβ1–40 (MW > 170 kDa), and a concomitant decrease of low-molecular weight Aβ1–40 (MW < 17 kDa) are seen with increasing incubation time. Among all the time points, the 1-week incubation yielded a relatively higher percentage of fibrillar Aβ1–40 compared to monomeric and dimeric species than the other time points. b Representative confocal microscopic images showed significantly more MAC deposits (Cy3, red) on ARPE-19 cells by combinatorial stimulation of fibrillar Aβ1–40/NHS or zymosan (Zym)/NHS than by NHS alone. HI-NHS replacement abolished MAC deposition on RPE cells regardless the presence of fibrillar Aβ1–40 or Zym. Scale bars; 20 μm. c Stimulation with fibrillar Aβ1–40 or Zym (positive control) in the presence of NHS resulted in a greater percentage of MAC-labeled RPE cells than in the presence of HI-NHS (Mann-Whitney, p ≤ 0.05). The control bars indicate background level of MAC labeling as demonstrated by incubating ARPE19 cells with NHS, and this resulted in higher labeling than in HI-NHS (Mann-Whitney, p ≤ 0.05). Comparisons between the three groups, fibrillar Aβ1–40, zymosan, and control, in the presence of NHS, demonstrated significance between fibrillar Aβ1–40 and control, as well as between zymosan and control but not between fibrillar Aβ1–40 and zymosan (Kruskal-Wallis, p ≤ 0.05)