FIG. 4.

Production of PGE₂ by human intestinal xenografts in response to infection with E. histolytica is largely blocked by pretreatment of host mice with indomethacin (Indo; 1.5 mg/kg every 8 h) or NS-398 (1 mg/kg every 8 h). Mice received indomethacin, NS-398, or vehicle beginning 1 h prior to infection of the xenograft with trophozoites; 24 h after infection, the mice were killed and the PGE₂ content of human intestinal xenograft tissue was determined by enzyme immunoassay. Data are means ± standard errors of the means for 5 to 12 xenografts. ∗, P < 0.001 compared with uninfected xenograft alone; ∗∗, P < 0.001 compared with E. histolytica alone.