T-cell response to CII. Influence of thymectomy (Tx) on the T-cell response to CII peptides of MMC or littermate (lm) mice. Activation of lymph node cultures with different antigens; 50 μ g/ml synthetic CII 256-270 peptide, 50 μ g/ml glycosylated CII 256-270 peptide, 10 μ g/ml purified protein derivative. Backgrounds are cultures in which no antigen was added. The results after stimulation with purified protein derivative (positive control) are shown in the left, proliferative response towards CII peptides are shown in the middle and the IFN-γ production is shown in the right part of the figure, respectively. The background IFN-γ values below 0.01U/ml are not indicated in the figure. At the indicated times after thymectomy (4 weeks [4w] or 8 weeks [8w]), the indicated number of mice were immunized with rat CII and 10 days later the LNCs were isolated. Each bar represents the mean value ± standard error. Both proliferation (as measured with thymidine uptake) and IFN-γ contents in the supernatants are indicated. *P < 0.05, **P < 0.01, ***P < 0.001, versus background.