FIG. 5.

Enhanced replication in IFN-γ-treated MΦs is a unique property of amastigotes and is not mediated by IL-10. MΦs (3 × 10⁵ cells/well) were infected with 1.5 × 10⁶ metacyclic promastigotes or 4.5 × 10⁵ amastigotes in 24-well plates. All parasite burdens were determined at 48 h postinfection. (A) C57BL/6 BM-MΦs either were not treated or were treated with 20 ng of IFN-γ per ml and then infected with metacyclic promastigotes that had been preincubated without serum, with 5% L. amazonensis-specific antiserum, or with normal mouse serum. (B) C57BL/6 BM-MΦs were not treated or were treated with 20 ng of IFN-γ per ml and then were infected with tissue-derived or MΦ-derived amastigotes. (C) Before infection with amastigotes, C57BL/6 BM-MΦs were pretreated with 20 ng of IFN-γ per ml in the presence or absence of 10 μg of anti-IL-10 MAb per ml. As controls, cells were treated with 20 ng of IL-10 per ml together with or without 10 μg of anti-IL-10 MAb per ml. All data are the means ± standard deviations for three wells. One asterisk indicates that the P value is <0.05, and two asterisks indicate that the P value is <0.01.