Whole blood stimulation assay.

<p>A: Whole blood was stimulated with LPS (left panels) or PHA (right panel). <i>Upper panels:</i> concentration dependent inhibition of CD54 (ICAM-1) expression on monocytes by the indicated IVIG fractions was monitored by flow cytometry. MFI: mean fluorescence intensity. <i>Lower panels:</i> concentration dependent inhibition of MCP-1 (CCL2) release by IVIG was quantified by ELISA in the supernatant of stimulated blood cultures. Mean values from representative experiments using blood from single donors are shown. neg: no stimulation, pos: stimulation without IVIG, FT: flow through, E1/E2 SNA binding IVIG fractions, NAase: neuraminidase treated. B: Inhibition of PHA mediated MCP-1 release by Fc and F(ab')₂ fragments. <i>Left panel:</i> Mean MCP-1 concentration of stimulated minus non stimulated samples from a representative experiment is shown. <i>Right panel:</i> PHA stimulated whole blood was treated with 40 µM IgG, Fc, F(ab’)₂ or highly sialylated Fc (S+Fc). Normalized values from experiments with blood from two donors are shown. S+ Fc: SNA binding Fc fraction (highly sialylated Fc).