0001), IgG1 (p < 0.0001), IgG2a (p < 0.0001),
IgG2b (p = 0.0094) and IgG3 (p = 0.0003) but not for IgA (p = 0.5164) or IgM (p = 0.0783) antibodies. As disclosed before challenge, the IgG1 and the IgM antibodies were strongly enhanced by all the saponins ( Fig. 2). In the case of IgM, a significant enhancement was also noted after infection AZD6244 in the saline controls. Following the R saponin positive control, the CA4 saponin raised more IgG and IgG2a antibodies to the FML antigen than the CA3 saponin ( Fig. 2). Indeed, the average absorbance of CA4 increased from 0.564 before to 1.189 after infection (p = 0.0079) while the average for CA3 vaccinated mice did not significantly changed (from 0.718 to 0.689; p = 0.114). Furthermore, the CA4sap vaccine IgG2a response after infection was not statistically different from the saponin R vaccine. All saponins raised equivalent levels of IgG1 above the saline control and only the R saponin significantly enhanced the IgGb and IgG3 antibodies above saline controls ( Fig. 2). The IgA antibodies, on the other hand, were R428 enhanced in all groups after challenge ( Fig. 2). The predominance of the CA4 saponin,
although only modest after immunization, was more evident after infection. Indeed, compared to the respective antibody titers before infection, significant increases were detected in the CA4 saponin vaccinated mice after challenge for IgA (p = 0.0032), IgM (p = 0.0124), IgG (p = 0.0414), IgG2a (p = 0.0061) and IgG2b (p = 0.0349) antibodies while the CA3 saponin vaccine only showed an increase of the IgA (p = 0.0016) and ADP ribosylation factor IgM antibodies (p = 0.0045). These results confirm the higher potency of the 4 sugar chain CA4 saponin ( Fig. 1) in the induction of anti-FML specific antibodies that was further enhanced after the infective challenge. The cellular immune response was initially evaluated by the intradermal reaction against Leishmania lysate (IDR) ( Fig. 3). IDR was measured in the right hind footpads and subtracted from the values of the left hind footpad injected
only with saline. At 24 h after immunization, the IDR response was significantly higher for the R saponin compared to all the other groups and also higher for the CA3 (mean = 0.06 mm) and CA4 (mean = 0.08 mm) than for the saline control (mean = 0.02 mm) ( Fig. 3A). At 48 h only the R and CA4 sustained this response indicating the superiority of CA4 over the CA3 saponin of C. alba. After challenge, only the R saponin vaccine sustained the enhanced IDR ( Fig. 3B). There was no significant variation, before and after infection, in the magnitude of the IDR response induced by the CA3 (p = 0.8103 at 24 h and p = 0.6818 at 48 h) or by the CA4 vaccines (p = 0.3898 at 24 h and p = 0.2801 at 48 h) ( Fig. 3A and B).