Noggin gene transfer prevents arthritis. (A) RT-PCR demonstrating enhanced expression of noggin 72 hours after cDNA gene transfer (300 μg and 30 μg). Little endogenous noggin is found. The RT-negative control (RT-neg) obtained from muscle injected with 300 μg pcDNA3.1+noggin shows that the RNA extraction procedure successfully removed most of the potentially contaminating cDNA. (B) Real-time PCR analysis of noggin expression 72 hours after cDNA gene transfer. Mean ± SD from 2 samples. (C) Immunoprecipitation and Western blot demonstrating expression of noggin 72 hours after intramuscular plasmid cDNA gene transfer. A 26-kDa band corresponding to noggin was found in 2 different mice after gene transfer in the injected tibialis anterior muscle (right muscle, lanes 1 and 3) but was absent in contralateral control muscle (left muscle, lanes 2 and 4). Noggin was also detected in the serum of both noggin plasmid-injected mice (lanes 5 and 6) but not in control mice (lanes 7 and 8). Lane 8 shows a positive control using recombinant noggin-Fc. (D) Noggin gene transfer significantly reduced incidence of spontaneous arthritis as compared with empty vector–treated animals. *Gehan-Wilcoxon test, P < 0.05. (E) Noggin gene transfer (300 μg or 30 μg) significantly reduced severity of spontaneous arthritis as compared with that in empty vector–treated animals. *Mann-Whitney U test; P < 0.05 at week 25. (F) Noggin gene transfer significantly reduced time-integrated clinical severity, expressed as area under the curve, as compared with that in control animals. *Mann-Whitney U test; P < 0.05. (D and E) Data are shown as mean ± SEM; n = 8 or 9 mice per group.