Evaluation of immune response against cutaneous leishmaniasis induced by alginate microspheres encapsulated with autoclaved Leishmania major (ALM), Quillaja saponin or CpG-ODN adjuvants

Leishmaniasis caused by compulsory intercellular parasite of leishmania. Suitable immunity for this infection is cellular immunity that depends on CD4+ T cell. Vaccination is a suitable way for controlling the disease and autoclaved leishmania major is a suitable choice for preparation of vaccine against this disease.Particulate drug delivery systems such as microspheres increase the immune response against encapsulated antigen and have immunoadjuvant potential. Alginate microspheres have been used for vaccination in several imunisation studies. Saponins have also shown high immune stimulation potential both for Th1 and Th2. CpG-ODN can be used as an immunity adjuvant for vaccines for increasing the immune responses. In this investigation various formulations of ALM (free or encapsulated in microsphere) with saponin and CpG-ODN adjuvants have been studied to find the best formulation for leishmaniasis vaccine. Also various formulations of ALM (free or encapsulated in microspheres alone or with CpG-ODN or saponin) were injected to balb/c mice. S.C. immunizations were repeated three times in three weeks intervals. For challenge test, after the last immunization, 106 live promastigotes were injected to the left foot pad of mice and foot pad thickness was recorded until 70 days. Serum antibody titers were determined three weeks after the last immunization by an ELISA method. For cytokine assay, the spleen lymphocytes were incubated with recall antigens and IFN-γ and IL-4 titers were determined in culture supernatant with a sandwith ELISA method. Results of this investigation showed that saponin and CpG have immunoadjuvant property in leishmania vaccine.(ALM)+SAP showed better result in immunostimulation (P<0.001). Addition of saponin and ALM in microsphere (ALM+SAP) increased the concentration of IFN-γ but didn’t have significant effect on concentration of IL-4 (P>0.05). Encapsulation of ALM and CpG in alginate microspher showed higher concentration of cytokines than CpG solution (P<0.001). So that we can not choice one of these adjuvants is better by results of this investigation and investigation must be continue for better result and selection one of this adjuvant.