Recombinant limitin inhibits IL-7–dependent colony formation and is stable to both acid and heat treatment.

(A) The indicated concentrations of recombinant limitin were added to CFU–IL-7 cultures. The results are shown as means ± SDs of triplicate cultures. (B) Recombinant limitin or IFN-γ was treated with acid (pH 2) or heat (56°C) for 30 minutes. The indicated concentrations of treated factors were added to CFU–IL-7 colony assays. The results are shown as means ± SDs of triplicate cultures. Similar results were obtained in 2 independent experiments.