Figure 7

Modulation of CD148 phosphatase activity in CD4⁺ T cells by synovial fluid, hydrogen peroxide and tumour necrosis factor. Human CD4⁺ T cells were isolated and activated using anti-CD3 and gamma-irradiated EBV B cells. Two days after activation cells were treated with the indicated concentrations of synovial fluid (A), hydrogen peroxide (B) or 0.1 ng/ml TNFα (C) as described in Materials and methods. CD148-associated tyrosine phosphatase activity was measured by a fluorescence assay as described in Materials and methods. EBV, Epstein-Barr virus; TNFα, tumour necrosis factor alpha. Bars indicate SEM; n = 8 (for panel A); n = 3 (for panels B and C).