Fig. 6.

BT assays of macrophage-conditioned supernatants of BL/6, MRL-Mp, NZB/W. (a) Despite slightly higher levels of Dnase1l3 protein (upper 34 kD and lower 28 kD band) in cell lysates from SLE macrophages (n = 2 mice), the FD nuclease activity in macrophage-conditioned media was lower than that of BL/6. Lower register shows an anti-GFP Western blot of lipofected HeLa cells exposed to macrophage-conditioned media. Media conditioned by cells from SLE mice with 89I mutation had less capacity to block GFP gene transfection; hence, SLE macrophages had a deficiency of BT activity. (b) Percentage of gated cells that were GFP positive by flow cytometry of transfected HeLa cells are depicted by graphs with ± standard deviation (n = 4 trials). Media conditioned by unstimulated macrophages from both MRL-Mp and NZB/W mice fail to erect a barrier relative to BL/6. NZB/W mice had less BT activity than MRL mice. Even after IFN-γ induction, these differences were maintained; however, BT activity remained significantly diminished only in NZB/W mice.