Evaluation of vaccinal effectiveness of preparations containing membrane antigens of Leishmania (L.) amazonensis in experimental cutaneous leishmaniasis model

Abstract

American tegumentary leishmaniasis (ATL) is considered a neglected disease, for which an effective vaccine or an efficient diagnosis is not yet available and whose chemotherapeutic arsenal is threatened by the emergence of resistance by etiological agents such as Leishmania amazonensis. ATL is endemic in poor countries and has a high incidence in Brazil. Vaccines developed from native parasite fractions have led to the identification of defined antigenic subunits and the development of vaccine adjuvant technology. The purpose of the present study was to develop and compare preparations based on membrane antigens from L. amazonensis, as a biotechnological prototype for the immunoprophylaxis of the disease in a murine experimental model. For this purpose, batches of biodegradable polymeric micro/nanoparticles were produced, characterized and compared with other parasite's antigens in solution. All preparations containing membrane antigens presented low toxicity on murine macrophages. The in vivo evaluation of immunization efficacy was performed against a challenge with L. amazonensis, along with an evaluation of the immune response profile generated in BALB/C mice. The animals were followed for sample processing and quantification of serum-specific cytokines, nitrites and antibodies. The sera of animals immunized with the non-encapsulated antigen formulations showed higher intensities of nitrites and total IgGs. This approach evidenced the importance of the biological studies involving the immune response of the host against the parasite being interconnected and related to the subfractionation of its proteins in the search for more effective vaccine candidates.

High-through identification of T cell-specific phage-exposed mimotopes using PBMCs from tegumentary leishmaniasis patients and their use as vaccine candidates against Leishmania amazonensis infection

“…In addition, it should not require the association of immune adjuvants to increase its immunogenicity, since there are few of these licensed products for the use in dogs and humans (Reed et al ., 2016). So far, most of the parasite proteins tested as recombinant vaccines against L. amazonensis infection needed the association of adjuvants (Coelho et al ., 2003; Ramírez et al ., 2014; Martins et al ., 2017 a , 2017 b ; Ribeiro et al ., 2017). Another candidate, the Leishvacin ® , which is composed of total L. amazonensis antigenic preparations, was tested as vaccine against infection by the parasites.…”