Fig. 4.

C1q alters GM-CSF + IL-4 induced DC differentiation. Monocyte-DCs were isolated and cultured in the presence of GM-CSF + IL-4 (G4) and with or without 25 μg/ml C1q (A–C). For the dose-response experiments, several concentrations of C1q were added as indicated (D). (A) C1q significantly decreased CD86 expression in monocyte-DCs compared to G4. *P <0.05, **P <0.01 (n = 4). (B) Monocyte-DCs cultured in the presence of C1q showed a decrease in the percentage of CD83⁺ cells in comparison with cells cultured in G4 alone. While CD83 expression was detected on the surface of these cells, their MFI remained low throughout the days with or without the addition of C1q (data not shown). *P <0.05 (n = 4). (C) CD11c expression was increased by day 2 with the addition of C1q compared to day 0. There was no significant difference in CD11c expression levels on cells cultured with or without C1q (n = 6). (D) Dose-response analysis revealed that there was little or no difference in the distribution of HLA-DR between C1q treated versus untreated cells on day 2 (n = 3). Cells were gated on HLA-DR⁺ cells for all experiments.