Figure 4. T15-NAb inhibits in vitro TLR induced maturation of conventional DC.

Bone marrow mononuclear cells were cultured with GM-CSF and IL-4 for 5 days, then purified with anti-CD11c beads prior to overnight culture in serum-free media. (A) LPS induces maturation of DC, based on increased CD80 and IL-12p40 expression, which is inhibited by T15 IgM (20 μg/ml) in cultures supplemented MBL (20 μg/ml) and C1q (80 μg/ml). DC are shown to be heterogeneous in their level of maturation, even in the absence of LPS or poly I:C. Based on scattergram analysis, these overnight cultures contained 10–18% dead cells and fragments. (B) T15-NAb, in the presence of MBL and C1q, inhibits LPS induced DC maturation. Values for CD80⁻ IL-12p40^low DC, as gated in panel A, is shown from four or more replicate cultures (mean+/− SEM). (C) T15-NAb, in the presence of MBL and C1q, inhibits poly I:C induced DC maturation. Data from four or more replicate cultures are shown. Open bars are without IgM, dark bars are with Isotype control, and vertical strips are with T15 IgM at 20 ug/ml. Significance as indicated: * P<0.05; ** ≤ 0.01; *** ≤0.0001; **** ≤0.0003. Representative of three independent experiments.