Treatment with anti-TNF-α monoclonal antibodies inhibits proinflammatory cytokine production in Tg197 mice. (a) Sera were collected from young animals at the indicated times. Levels of hTNF-α were determined by ELISA and expressed as mean ± SEM of each group. (b-d) Detection of proinflammatory cytokines, murine IL-6, IFN-γ, and IL-1β mRNA in joint tissue of aged mice. RNA was extracted from the joint tissues of the mice at baseline and 6 weeks after treatment with either saline or anti-TNF-α mAb. An RNase protection assay was then performed. The ratios of individual cytokine mRNA to GAPDH in animals treated with anti-TNF-α mAb are compared with those in saline-treated animals or animals at baseline. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; mAb, monoclonal antibody; TNF, tumor necrosis factor.