| dc.description.abstract | Leishmaniasis is one of the neglected diseases that afflicts residents of developing
countries. To date, there are no proven vaccines against this disease. Previous studies
have shown that Leishmania major soluble exo-antigens (LmSEAgs) alone have the
potential to confer protection to mice infected with L. major. There was need to
investigate whether adjuvants could enhance the protective effects of the LmSEAgs the
subject of this thesis.
In this study, the immunoprophylatic and immunotherapeutic potential of Bacille
Calmette Guérin (BCG) as an adjuvant was investigated. For immunoprophylaxis,
susceptible BALB/c mice were vaccinated with LmSEAgs with or without BCG on day 0
and boosted on day 13, then challenged with L. major metacyclic promastigotes a week
later. The control group was unvaccinated. While for immunotherapy, mice were
vaccinated with LmSEAgs with or without BCG at day 21 and boosted on day 35.
Disease progression was determined by measuring the size of lesions and quantifying
parasite burdens in L. major infected footpads using a limiting dilution assay. While
cytokine production from splenocytes was determined by flow cytometry.
For both immunoprophylaxis and immunotherapy, mice produced significantly high
levels of IFN-γ (P< 0.05) and low levels of interleukin IL-4, (P< 0.05) compared to the
unvaccinated mice. This was corroborated with reduction in lesion sizes and parasite
burden compared to the controls (P< 0.05). In comparison to the group of mice treated
with LmSEAgs alone or BCG alone there was no significant difference in the levels of
IFN-γ produced, lesion size reduction or parasite burdens (P>0.05) in both
immunoprophylaxis and immunotherapy.
In conclusion, the results show that BCG does not enhance the protective effect of
LmSEAgs. Further studies should be done to search for molecules with potential of
enhancing the immunotherapeutic and immunoprophylactic effects of LmSEAgs. | en |
