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. 2020 Aug 26;9(9):793. doi: 10.3390/antiox9090793

Figure 1.

Figure 1

hpRPE cells express and secrete complement components. (A) mRNA expression of main complement components of the classical (C1Q), central (C3) classical/lectin (C4A, C4B), terminal (C5) and alternative (CFB, CFD) complement pathway was detected in hpRPE cells. hpRPE cells expressed also mRNA of soluble (CFI, CFH, CFP) and membrane bound (CD46, CD59) complement regulators, and transcripts of complement receptors: anaphylatoxin receptors (C3AR, C5AR1), opsonin receptor CR3 subunit (CD11B). Shown expression data of donor 1 are representative for mRNA experiments in hpRPE cells of donors 1–4 (Table 1). (B) Activation products of the central complement component C3 [(blot left, arrows) C3b (115 kDa), C3dg (39 kDa) and C3d (35 kDa)] were detected in hpRPE. Multiple bands were identified in hpRPE cells using an anti-complement regulator CFI antibody (blot center, arrows for full CFI (80 kDa) and two CFI disulfide linked chains (50 kDa, 30 kDa)). Anaphylatoxins C3a and C5a (blot right) were found in cell lysates of hpRPE cells. Examples of whole blots are depicted in (B) for donor 5 (C5a) and donor 6 (C3, C3a, CFI). (C) hpRPE cells secrete C3, C4, CFB, CFD and the regulators CFI as well as CFH into the cell culture supernatant (pooled data of two eyes, apical and basal supernatant are shown, details for hpRPE cells of donors 11–16 are presented in Figure S3). Mean with standard deviation is shown. Dotted line depicts blank control. MFI—mean fluorescence intensity.