Fig. 2.

Recombinant BmpA selectively reconstitutes the ability of bmpA/B mutant B. burgdorferi to induce cytokine expression. Synovial cells were exposed to B. burgdorferi bmpA/B mutants (bmpA/B⁻) for 12 hours in the absence or presence of recombinant B. burgdorferi proteins (300 nanogram/ml), BmpA, BmpB and BB0365 (control). Parallel wells were treated with 10 ug/ml of polymyxin B (PB) before addition of B. burgdorferi. Expression of TNF-α (black bar) and IL-1β (gray bar) were measured by quantitative RT-PCR analysis and normalized to the level of β-actin. Levels of cytokine transcripts in the untreated cells and in cells exposed to either wild type spirochetes or bmpA/B mutants were shown. Bars represent the mean ± standard error from three independent experiments. Unlike corresponding concentration of BmpB and BB0365, only BmpA (300 nanogram/ml) was able to reconstitute the ability of bmpA/B⁻ to induce the cytokine response (P< 0.05).