Trypanosoma cruzi trans-Sialidase in Complex with a Neutralizing Antibody: Structure/Function Studies towards the Rational Design of Inhibitors (original) (raw)
Figure 2
Reactivity of mAb 13G9 with T. cruzi parasites.
A) T. cruzi surface labeling by the 13G9 mAb. Epifluorescence microscopy of T. cruzi trypomastigotes, seeded onto poly-L-lysine-treated coverglasses, and immunolabeled with 13G9 mAb followed by a secondary FITC-labeled antibody. B) Inhibition of parasite sialylation. Trypomastigotes obtained from cell cultures made in ‘low sialyl-donors’ conditions, were sialylated with TS and sialyllactose, in the presence of mAb 13G9. Total sialic acid was quantified by the thiobarbituric acid method and referred to re-sialylated parasites in the absence of mAb as 100% (approximately 1.2 pmoles of sialic acid/106 parasites). C) Effect of mAb 13G9 in infection assays on mammalian cells. Parasites were preincubated for 1 h with 13G9 antibody (100 µg/ml) before infection. After 24 hrs, infected cultures were fixed and stained with Hoescht 33342. At least 300 cells were counted.