Co-administration of chitin micro-particle and Leishmania antigen proposed a new immune adjuvant against experimental leishmaniasis

Aims We investigated the protective effect of chitin micro-particle (CMP) as an adjuvant against Leishmania infection in BALB/c mice. Methods Mice were immunized subcutaneously with soluble Leishmania antigen (SLA) plus CMP (100 mu g SLA + 100 mu g CMP/100 mu L) as the test group. Three weeks after the last immunization, test and control groups were infected by Leishmania major (L major). Eight weeks post-infection, evaluation of parasites load in lymph nodes was performed using limiting dilution assay. Then, the spleen cell cytokine response (TNF-alpha, IFN-gamma, IL-4, IL-10, IL-17 and IL-27) to SLA among vaccinated and nonvaccinated groups was investigated using ELISA. Serum levels of IgG1 and IgG2a were measured as well. Results The SLA plus CMP group demonstrated the protection. The responses included reduced lesion formation and lower parasite load. Also, in comparison with control group higher levels of IFN-gamma and, IL-10 in the culture of spleen cells, and lower levels of IgG1 in sera were seen in SLA plus CMP group. Conclusion The data supported the possibility of using CMP as a suitable adjuvant in Leishmania vaccination.