Cytokine and nitric oxide patterns in dogs immunized with LBSap vaccine, before and after experimental challenge with Leishmania chagasi plus saliva of Lutzomyia longipalpis.

In the studies presented here, dogs were vaccinated against Leishmania (Leishmania) chagasi challenge infection using a preparation of Leishmania braziliensis promastigote proteins and saponin as adjuvant (LBSap). Vaccination with LBSap induced a prominent type 1 immune response that was characterized by increased levels of interleukin (IL-) 12 and interferon gamma (IFN-γ) production by peripheral blood mononuclear cells (PBMC) upon stimulation with soluble vaccine antigen. Importantly, results showed that this type of responsiveness was sustained after challenge infection; at day 90 and 885 after L. chagasi challenge infection, PBMCs from LBSap vaccinated dogs produced more IL-12, IFN-γ and concomitant nitric oxide (NO) when stimulated with Leishmania antigens as compared to PBMCs from respective control groups (saponin, LB- treated, or non-treated control dogs). Moreover, transforming growth factor (TGF)-ß decreased in the supernatant of SLcA-stimulated PBMCs in the LBSap group at 90 days. Bone marrow parasitological analysis revealed decreased frequency of parasitism in the presence of vaccine antigen. It is concluded that vaccination of dogs with LBSap vaccine induced a long-lasting type 1 immune response against L. chagasi challenge infection.

Safety and toxicity of a new formulated Leishmania major preliminary vaccine in animal model Balb/c and small white conventional laboratory mice.

Leishmania parasites cause a spectrum of diseases that afflict the populations of 88 countries around the world and all attempts to control leishmaniasis have failed. It seems that preparing a vaccine may be the final solution. The aim of this study was to determine various Leishmania (L.) major antigens vaccine candidates and effects of the vaccine on delayed type hypersensitivity (DTH). Many different methods of vaccine preparation plus or without adjuvant were used. We prepared crude antigen combinations by five different methods using antigens from L. major parasites. Phase I was done in animals. The immunogenic effect was evaluated with the delayed type hypersensitivity (DTH) reaction with five different doses, including 100, 200, 300, 400, 500 microg/ml of total protein + BCG in Balb/c and conventional laboratory white mice (out breed). Our results showed that the cocktail antigen was highly specific. No injection of BCG solvent or saline treated controls showed significant results. Taken together, the effect of cellular immune response to the cocktail vaccine induced a significant effect against cutaneous leishmaniasis in the experimental model of vaccine with L. major.