Nitric oxide concentration in splenocyte cultures from mice immunized with Leishmania promastigote extract (LE) and babassu aqueous extract (BAE). Supernatants were obtained from unstimulated spleen cells, i.e, spleen cells that were not incubated with antigen in vitro. Spleens were collected ten days after the end of the immunization from groups of five to nine BALB/c mice that had been immunized with two subcutaneous injections of LE associated with BAE (LE + BAE) or of Al(OH)3-adsorbed LE associated with BAE (LE-Al(OH)
+ BAE), 14 days apart. Groups of control mice were also immunized with LE emulsified in complete Freund's adjuvant (LE + CFA), with LE without BAE (LE), and with Al(OH)3-adsorbed LE without BAE (LE-Al(OH)
), following the same immunization protocol. Each injection contained a total of 250 μg of LE and/or 5 mg of BAE. A negative control group was injected with a saline solution in place of the immunizing injections (Saline). The boxes represent the 10-90 percentile intervals and the median values of the results, and the vertical bars the value ranges. P < 0.001, Kruskal-Wallis test. *, P ≤ 0.003; **, P ≤ 0.005; ***, P ≤ 0.016; Mann-Whitney U test.