Evaluation of the Immunogenicity of a DNA Vaccine for Leishmania Major based on LACK antigen using Calcium Phosphate and Chitosan Adjuvants

Abstract

Abstract Leishmaniasis is a parasitic disease of global health concern, and an affordable and effective vaccine could be a valuable solution. The aim of this study was to evaluate the immunogenicity of a Leishmania major DNA vaccine based on LACK antigen using calcium phosphate and chitosan adjuvants nano particles. Seventy Balb/c female mice 4–6 weeks old and 20–22 g weight were selected and were divided into 5 groups [Each group 14 mice]. First Group received plasmid LACK vaccine [PCDN3 + LACK], second group received PCDN3 + LACK + Nano adjuvant phosphate Ca, third group received PCDN3 + LACK + Nano adjuvant chitosan, forth group received PBS as negative control and fifth group did not receive vaccine as positive control. The mice were vaccinated two times intramuscular injection with three weeks interval. The mice were challenged with wild type of Leishmania major promastigote via intra dermal injection into the basal of their tail three weeks after the last vaccination. Clinical sign and measuring the size of lesion were evaluated two times in every week. To assay immune system responses, IFN-gamma and IL4 were analysed using ELISA test after and before vaccination and challenging. The finding showed that PCDN3 + LACK + n anno chitosan, PCDN3 + LACK + nano calcium phosphate and PCDN3 + LACK [without adjuvant] groups had the highest increase in IFN- gamma titer and the greatest decrease of IL4 titer. The size of Leishmania lesion were decreased in vaccination groups and the best results were found in PCDN3 + LACK + nano chitosan at last week of challenging. Based on the results, vaccination with using of LACK antigen with nano calcium phosphate adjuvant and nano chitosan may be an effective approach for controlling cutaneous leishmaniosis in endemic region.