The different spatial conformation of the C-23 aldehyde group defines the type of induced immune response [17]. An enhanced humoral immune response

was obtained using an enriched axial aldehyde-containing sapogenin while an enhanced cellular immune response (increased DTH and IFN-γ sera levels) that determined a 77% reduction of liver parasitic load was obtained using an enriched equatorial aldehyde-containing QuilA-sapogenin [17]. The Q. saponaria saponins, which lack the hydrophobic moiety of QS21, are capable LY294002 cell line of inducing increases in DTH, CD4+ T lymphocytes in spleen, IFN-γ in vitro, body weight gain and a pronounced reduction of parasite burden in the liver, suggesting that the immunoprotective potential of the saponin relies more on its carbohydrate chains than on its hydrophobic attached moiety [10]. Similar to QS21, the CP05 saponin of Calliandra pulcherrima is composed of a triterpene nucleus with two carbohydrate fractions attached to C-3 and C-28, respectively, and one hydrophobic moiety acylated to a sugar attached to C-28 [24]. The chemical removal of the hydrophobic monoterpene moiety of CP05 did not interfere with the protection but the removal of one or two of the carbohydrate chains, however, abolished protection and determined an increase of the parasite

load indicating that, as postulated for other saponins [25], [26] and [27], and in the case of the CP05 saponin also, the induction of protection Mephenoxalone is directly KPT-330 nmr related to the presence of the carbohydrate moieties [14]. Considering the relevance of the carbohydrate moieties to the adjuvant potential of saponins, and the evidence that the immunoprotective potential increases in direct relation to the number of sugar units on the carbohydrate chains [19] and [22] this work investigated, two saponins of Chiococca alba (CA3 and

CA4) [28] which differ only in one sugar unit. These two saponins were compared in the murine vaccination against visceral leishmaniasis with the FML antigen. The QS21-containing saponin adjuvant of the Leishmune® vaccine (saponin R) was used as a positive control. The CA3 and CA4 saponins of C. alba are two typical Glucuronide Oleanane-type Triterpene Carboxylic Acid 3,28-O-Bisdesmosides (GOTCAB). Their structures were recently elucidated [28]. Both share a triterpene nucleus to which a glucuronic acid is attached at C-3 and an apiose–rhamnose and arabinose chain is attached at C-28 ( Fig. 1). The CA4 shows the same triterpene and sugar chains with one additional apiose unit 1 → 3 linked to the rhamnose unit of the C-28 carbohydrate chain ( Fig. 1). The QS21 saponin on the other hand is more complex but also, similar to the C.