Development of an immunogen containing CD4.sup.+/CD8.sup.+ T-cell epitopes for the prophylaxis of tegumentary leishmaniasis

• Published in: Applied microbiology and biotechnology Vol. 106; no. 12; pp. 4627 - 4641
• Main Authors: de Andrade Ferraz, Isabela, Carvalho, Ana Maria Ravena Severino, de Brito, Rory Cristiane Fortes, Roatt, Bruno Mendes, Martins, Vívian Tamietti, Lage, Daniela Pagliara, dos Reis Cruz, Luiza, Cardosa Medeiros, Fernanda Alvarenga, Goncalves, Denise Utsch, da Costa Rocha, Manoel Otavio, Ferraz Coelho, Eduardo Antonio, de Oliveira Mendes, Tiago Antonio, Costa Duarte, Mariana, Menezes-Souza, Daniel
• Format: Journal Article
• Language: English
• Published: Springer 01-06-2022
• Subjects: Antigenic determinants; Health aspects; Leishmaniasis; Prevention; T cells; Brazil
• ISSN: 0175-7598
• DOI: 10.1007/s00253-022-12033-7

Tegumentary leishmaniasis (TL) is a disease of high severity and incidence in Brazil, and Leishmania braziliensis is its main etiological agent. The inefficiency of control measures, such as high toxicity and costs of current treatments and the lack of effective immunoprophylactic strategies, makes the development of vaccines indispensable and imminent. In this light, the present work developed a gene encoding multiple T-cell (CD4.sup.+/CD8.sup.+) epitope, derived from conserved proteins found in Leishmania species and associated with TL, to generate a chimeric protein (rMEP/TL) and compose a vaccine formulation. For this, six T-cell epitopes were selected by immunoinformatics approaches from proteins present in the amastigote stage and associated with host-parasite interactions. The following formulations were then tested in an L. braziliensis murine infection model: rMEP/TL in saline or associated with MPLA-PHAD.sup.®. Our data revealed that, after immunization (three doses; 14-day intervals) and subsequent challenging, rMEP/TL and rMEP/TL + MPLA-vaccinated mice showed an increased production of key immunological biomarkers of protection, such as IgG.sub.2a, IgG.sub.2a/IgG.sub.1, NO, CD4.sup.+, and CD8.sup.+ T-cells with IFN-[gamma] and TNF-[alpha] production, associated with a reduction in CD4.sup.+IL-10.sup.+ and CD8.sup.+IL-10.sup.+ T-cells. Vaccines also induced the development of central (CD44.sup.highCD62L.sup.high) and effector (CD44.sup.highCD62L.sup.low) memory of CD4.sup.+ and CD8.sup.+ T-cells. These findings, associated with the observation of lower rates of parasite burdens in the vaccinated groups, when compared to the control groups, suggest that immunization with rMEP/TL and, preferably, associated with an adjuvant, may be considered an effective tool to prevent TL.