FIG. 1.

Effect of rmGM-CSF on the morphotype of T. cruzi trypomastigotes. (A) T. cruzi trypomastigotes were incubated with rmGM-CSF, or with a mixture of rmGM-CSF and an anti-GM-CSF MAb, a control MAb, or rmIL-2 for 7 h, and the percentage of spherical forms was counted. There were no spherical forms of trypomastigotes when parasites were treated with PBS-G, even after 24 h of incubation (not shown). Data are means ± SEM of three independent experiments performed in duplicate. ∗, P < 0.05 compared with trypomastigotes treated with rmGM-CSF alone (Mann-Whitney U test). (B) Kinetics of the morphotype change caused by rmGM-CSF determined by incubating T. cruzi trypomastigotes with rmGM-CSF (62.5 ng/ml) at 37°C for various time periods.