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. 2014 Nov 14;9(11):e112100. doi: 10.1371/journal.pone.0112100

Figure 2. Inhibitory effect of IgG on ApoCell-phagocytosis.

Figure 2

Purified serum IgG preparations from SS and SLE patients display inhibitory activity on ApoCell-phagocytosis by healthy MDM that correlates with its binding activity to early apoptotic cells. A. Purified serum IgG preparations from SS and SLE patients (but not RA) display significantly increased binding to early apoptotic cells. Binding index was normalized and expressed as fold increase over the binding of a purified IgG preparation from a HBD used in all experiments. B–D. Cross-admixture ApoCell-phagocytosis experiments demonstrating that the pretreatment of early apoptotic cells with purified serum IgG preparations derived from SS and SLE (but not from RA) results in decreased ApoCell-phagocytosis by healthy MDM, as compared to treatment with IgG from HBD. In B, data are expressed as percent of baseline ApoCell-phagocytosis values (e.g. treatment of apoptotic cells with PBS only, considered as 100%). Similar results were obtained by slightly different experimental setups assaying the ingestion of CFSE-labelled IgG-pretreated apoptotic cells by electronically gated CD14-stained MDM in dual-color flow cytometry (C; representative results from 3 independent experiments) or the uptake of pHrodo-SE-labelled apoptotic cells in single-color flow cytometry (D). E. Highly significant inverse correlation between the rates of ApoCell-phagocytosis obtained by the various purified serum IgG preparations used (shown in A) and the levels of anti-ApoCell antibodies in those preparations (shown in A).