FIG. 8.

Metacyclic trypomastigotes with reduced gp90 expression have an increased ability to invade host cells. Parasites, untreated (—) or treated for 24 h with the indicated phosphorothioate oligonucleotide, were incubated with HeLa cells for 3 h at 37°C. After washes in PBS and staining with Giemsa, the number of intracellular parasites was counted in a total of 500 Giemsa-stained cells. Values are means ± SD of four experiments performed in duplicate. The parasites treated with PS2, PS4, or PS5 entered HeLa cells in significantly higher numbers (P < 0.01) compared to the untreated control by Student's t test.