FIG. 1.

¹²⁵I-TGF-α binds to amastigotes, and this binding is inhibited by cold excess TGF-α and EGF. (A) TGF-α binds to amastigotes. (Inset) Scatchard analysis of the binding data. B/F, bound/free (unbound) TGF-α. (B) Competition of ¹²⁵I-TGF-α binding by TGF-α, EGF, and bovine pituitary extract. The same concentration of amastigotes (5 × 10⁶ parasites ml⁻¹) were preincubated with different excess amounts (0- to 100-fold) of cold EGF and TGF-α followed by exposure to ¹²⁵I-TGF-α. Bars show means for triplicate samples of one representative experiment (± 1 standard deviation) selected from three independent experiments with similar results. *, significant difference compared to values for 0 and 1:1 cold/labeled ratios or to bovine pituitary extract values for 0 to 1:100 cold/labeled ratios (P < 0.05). The results are representative of three independent experiments.