Differential protection induced by immunization with variable doses of a Leishmania antigenic extract against Leishmania amazonensis.

• Autor(a) principal: COELHO, V. T. S.
• Data de Publicação: 2019
• Outros Autores: CHÁVEZ-FUMAGALLI, M. A., RODRIGUES, F. M., OLIVEIRA, D. M., SILVA, J. A. O., COSTA, L. E., MENDONÇA, D. V. C., ARAÚJO, M. N., FOUREAUX, E. C. M., MARTINS, V. T., FIGUEIREDO, J. E. F., COELHO, E. A. F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1121134
• topic: Proteção diferencial; Tamanho inóculo; Vacina

Experimental vaccines have been developed to protect against leishmaniasis using the BALB/c mice model immunized with different immunogens, but an effective vaccine still does not exist. To determine factors inherent to immunogens that might abrogate vaccine-induced efficacy, our research sought to investigate the impact of immunization using variable doses (low, medium and high) of a known soluble Leishmania antigenic extracts (SLA), associated or not with alum, in order to determine the best dose of this vaccine immunogen able to induce the best level of protection in BALB/c mice against L. amazonensis infection. This work shows that the immunization´ model using a high inoculum (100 µg) of SLA results in the best level of protection against challenge. These mice presented significant reductions in the footpad swelling and parasite load; high levels of IFN-γ and IL-12, and low levels of IL-4, IL-10, TGF-β and Leishmania-specific IgG and IgE antibodies. Mice immunized with 50 µg of SLA present intermediate results of protection; on the other hand, mice immunized with 1 µg showed the worst results. Considering all the elements, it could be concluded that the model employing a high dose of SLA in BALB/c mice can bring about the development of a protective immune response in the animals, thus allowing for the protection against the disease. In addition, we understand that the definition of an ideal dose for each vaccine candidate appears to be fundamental to determining the phenotype of resistance and/or susceptibility in murine models to study leishmaniasis.