The CP05
saponin from Calliandra pulcherrima Benth, shows remarkable similarities to the
QS21 saponin of Quillaja saponaria Molina. Both shared a
monoterpene hydrophobic moiety, a glycidic chain attached to the
triterpene C28, and three
sugars attached to C3. Different from
QS21, the CP05 does not show the
aldehyde group in
triterpene C4 involved in TH1 response. Balb/c mice were immunized either intact
saponin (CP05), the
monoterpene-deprived (BS), the C28
carbohydrate-deprived (HS) or the sapogenin fraction, in formulation with the
FML antigen of Leishmania donovani and challenged with 2 x 10(8) amastigotes of L. chagasi. While the CP05 induced 90% survival and 92.1% parasite reduction, a 100% survival and 94.1% protection were detected after the BS-
vaccine treatment, indicating that the
monoterpene acylated moiety, absent in the BS
vaccine, is not necessary for the induction of a protective global TH1 response. Only the DTH response of BS
vaccines was mildly lower than that of CP05 vaccinees. Maximal anti-
FML antibody, CD4(+) and CD8(+) Leishmania specific lymphocytes, IFN-gamma splenocyte secretion, reduction in parasite load and survival was also detected for the BS
vaccine. The HSFML
vaccine showed diminished responses in all tested variables, except for IFN-gamma secretion, indicating that the integrity of the
carbohydrate moiety attached to C28 is mandatory for the these functions. No protection was induced by the sapogenin-
FML indicating that the CP05
triterpene which lacks the C4
aldehyde group, is not a immunostimulating compound. No contribution to protection was detected in the CP05
saponin treated control group supporting the specificity of the
FML antigenic preparation.