Figure 1.
Progression in log-transformed anti-ESP IgG1 and IgG2 titres during the onset of immunity.
The data presented here are the means of the log-transformed titres. The titre is taken to be the first dilution with an optical density of less than 0.4 measured at 405 nm. The sera were tested using an ESP-coated ELISA at days 0, 21, 42 and 56. The ESP used was identical in profile to the antigen of the vaccine.
Figure 2.
Progression in log-transformed anti-PSA IgG1 and IgG2 titres during the onset of immunity.
The data presented here are the means of the log-transformed titres. The titre is taken to be the first dilution with an optical density of less than 0.4 measured at 405 nm. The sera were tested using a PSA-coated ELISA at days 0, 21, 42 and 56. PSA is a dominant antigen in ESP and therefore a key antigen in the vaccine.
Figure 3.
Lymphoproliferation index 3 weeks after the completion of the primary vaccination course.
This assay detects the ability of the specific T cells produced as a result of vaccination to proliferate after being exposed to Soluble Leishmania Antigens (SLA). The lymphoproliferation index is the ratio of the mean optical density obtained for the SLA stimulated samples compared to the mean optical density obtained for the non-stimulated samples using a BrdU specific ELISA system.
Figure 4.
ELISpot detection of IFN-γ secreting lymphocytes 3 weeks after the completion of the primary course.
This assay detects the ability of lymphocytes to secrete IFN-γ after specific stimulation with SLA by detecting spots (which represent a clone of cells secreting IFN-γ) using specific biotinylated antibodies and an automated ELISpot reader. The data presented here are the number of spots per 2×105 cells after stimulation with SLA minus the equivalent value obtained with the negative control using medium alone.
Figure 5.
CMLA assay: inhibition of the macrophage parasitic index, iNOS activity and production of NO derivatives.
Panel A is a comparison of the ability of the macrophages to inhibit parasite multiplication before vaccination (D0) and 3 weeks after completion of the primary course (D62). It demonstrates the increase in the inhibition of the macrophage parasite index as a result of vaccination. Panel B Is a comparison of the rate of expression of iNOS in the macrophages before vaccination (D0) and 3 weeks after completion of the primary course (D62). Panel C is a comparison of the rate of production of NO derivatives from the macrophages to before vaccination (D0) and 3 weeks after completion of the primary course (D62). When these three measurements are consistent, this provides evidence of an increased NO-mediated pathway of parasite killing as a result of vaccination.