Figure 4. IFN-α can enhance autoreactive B cell responses to non-optimal DNA fragment ICs.

Proliferation of AM14 (A) and AM14/TLR9^−/− (B) B cells in response to 15 μg/ml F(ab')₂ goat anti-mouse IgM, 100 ng/ml CLO97, 1 μg/ml PS-ODN 1826, or fragment ICs (5 μg/ml 1D4 + 100 ng/ml of biotinylated dsDNA) in the presence or absence of 1000 U/ml IFN-α. (C, D) Proliferation of AM14R B cells in response to 5 μg/ml 1D4, 1 μg/ml OVA-bio, protein IC (5 μg/ml 1D4 + 300 ng/ml OVA-bio), or DNA ICs (5 μg/ml 1D4 + 100 ng/ml biotinylated mouse dsDNA or clone 11) in the presence or absence of 1000 U/ml IFN-α. Results are the mean ± SEM of 3 experiments. (E) Proliferation of AM14R B cells in response to increasing concentrations of PS-ODN 1826 or fragment ICs (1.5 μg/ml 1D4 + biotinylated dsDNA) in the presence or absence of 1000 U/ml IFN-α; results are representative of 3 experiments. AM14R B cells were incubated for 24 hrs in the presence or absence of 1000 U/ml IFN-α and surface levels of CD69 and IgM were measured by flow cytometry (F), or they were stimulated with fragment ICs (1.5 μg/ml 1D4 + 30 ng/ml biotinylated dsDNA), 5 μg/ml F(ab')₂ goat anti-mouse IgM, or 1 μg/ml PS-ODN 1826 and Ca²⁺ flux was measured by flow cytometry (G), or cell lysates were assayed for phospho-PLCγ2 (H); results are representative of 2 experiments.