Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis.

Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential.

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.