Nanomed. J. 7(1): 29-39, Winter 2020 RESEARCH PAPER Liposomes containing the imiquimod adjuvant as a vaccine in the cutaneous leishmaniasis model Ahmad Mehravaran 1, 2* , Hadi Mirahmadi 1, 2 , Javad Akhtari 3 1 Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis institute, Zahedan University of Medical Sciences, Zahedan, Iran 2 Department of Parasitology and Mycology, Faculty of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran 3 Toxoplasmosis Research Center, Department of Medical Nanotechnology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran * Corresponding Author Email: ahmadmehravaran55@gmail.com- Note. Tis manuscript was submitted on September 30, 2019; approved on December 1, 2019 How to cite this article Mehravaran A, Mirahmadi H, Akhtari J. Liposomes containing the imiquimod adjuvant as a vaccine in the cutaneous leishmaniasis model. Nanomed J. 2020; 7(1): 29-39. DOI: 10.22038/nmj.2020.07.04 ABSTRACT Objective(s): Attempts to produce vaccines for leishmaniasis need adjuvants to trigger the kind of immune reaction required for protection. In this study, we examined the properties of the TLR7 agonist imiquimod, a vaccine adjuvant, making use of a live model of infection where the immune reactions could be identifed prior to and following the challenge of infection. Materials and Methods: Te liposomes of EPC containing the imiquimod adjuvant were prepared and characterized for protein concentration, surface charge, and particle size. Vaccination was done using the soluble Leishmania antigen (SLA) as a frst-generation vaccine model in the liposomal state to vaccinate BALB/c mice against the challenge of leishmania major. BALB/c mice were vaccinated subcutaneously, three times at a two-week interval. Parasite burden, footpad swelling, IgG isotype, as well as the level of IL-4 and IFN-γ were assessed as the protection criteria. Results: Te group of mice vaccinated by Lip+Imiquimod+SLA demonstrated a lower amount of footpad swelling and parasite burden than the bufer group. In addition, the highest level of IFN-γ and the lowest level of IL-4 production was noticed in the splenocytes of the mice vaccinated with the formulation of Lip+Imiquimod+SLA. Conclusion: Tese results imply that imiquimod added to the formulation of liposomes is able to modulate the immune reaction of the BALB/c mice vaccinated preferably to a T1 reaction rather than a T2 reaction which can also lead to partial protection against the challenge of Leishmania. Keywords: Adjuant, Leishmaniasis, Imiquimod, Liposome, Vaccine INTRODUCTION Leishmaniasis, is a parasitc vector-borne disease, which poses a signifcant public health threat globally. Based on a report by the WHO, this disease afects approximately 12 million individuals in 88 world countries, with about 350 million other individuals being in danger [1]. Leishmaniasis is an ignored tropic disease, which afects the poverty-stricken people, for whom getng access to efectve treatment and diagnosis is hard. Individuals inficted with the Leishmania show many symptoms, including the self-healing dermal lesion (CL) as well as the possibly deadly visceral type of the disease, ttled ‘visceral leishmaniasis[2] .Many eforts have been made to discover new medicines for treatng this disease, yet pentavalent antmonials are the most prevalent compounds to treat the disease, which were introduced more than 50 years ago. Medicines utlized for the treatment of leishmaniasis have some constraints, including resistance development, long treatment tme, strong side efects and high toxicity. In spite of the latest advancements in molecular immunology and pharmaceutcs, no authorized vaccine is present against leishmaniasis up to now [3]. In all leishmaniasis types, T lymphocytes