Figure 2

Inhibition of IL-1-mediated thymocyte proliferation. A. Thymocyte proliferation induced by 0.3 ng/ml of IL-1β (β; grey bar) could be inhibited in a dose-dependent fashion by a standard preparation of wild type human IL-1ra expressed in E. coli (open triangles). The IL-1 inhibitory activity of the wild type IL-1ra reference standard was compared to that of the culture supernatant of recombinant S. gordonii GP1300 (solid triangles), which contained 0.1 mg/litre RVFP/IL-1ra (as assessed by ELISA). B. Thymocyte proliferation to 0.3 ng/ml IL-1β (β; grey bar) was inhibited in a dose-dependent fashion by both the wild type IL-1ra reference standard (open triangles) and the recombinant RVFP/IL-1ra expressed in E. coli (solid squares). Results are the mean ± SEM of 3–9 replicate determinations within single experiments, representative of five performed. SEM lower than 10 % are not shown. Background thymocyte proliferation in culture medium without IL-1β (m, open bar) is also reported.