FIGURE 3.

Metacylogenesis and infectivity of L. major ATG4 null mutants. A, the percentage of metacyclic promastigotes in stationary phase populations of promastigotes was determined by the peanut lectin agglutination method. Values shown are the mean ± S.D. from three independent experiments. *, data for Δatg4.1 differed significantly from those for WT promastigotes at day 7 (p < 0.01). B, extracts of 10⁷ stationary phase promastigotes at day 7 (D7) or day 10 (D10) were assessed for metacyclic-specific proteins by Western blot analysis with anti-SHERP and anti-HASPB antibody. Cysteine synthase (CS) served as a loading control. C and D, mouse peritoneal macrophages were infected in vitro with stationary phase promastigotes or amastigotes isolated from lesions in BALB/c mice. Cells were assessed at 1 and 5 days post-infection for the percentage of infected macrophages. Data are mean ± S.D. and are representative of three independent experiments. *, infection level of ATG4 null mutant lines differed significantly from those of WT parasites (p < 0.05). E–H, BALB/c mice were infected with 2 × 10⁷ promastigotes or amastigotes and footpad lesion size was monitored weekly. Data are mean ± S.D. of five mice. *, infection level of ATG4 null mutant lines differed significantly from those of WT or the re-expressing line (p < 0.05).