Co-Administration of a Plasmid DNA Encoding IL-15 Improves Long-Term Protection of a Genetic Vaccine against Trypanosoma cruzi

• Autor(a) principal: Eickhoff, Christopher S.
• Data de Publicação: 2011
• Outros Autores: Vasconcelos, Jose Ronnie Carvalho de [UNIFESP], Sullivan, Nicole L., Blazevic, Azra, Bruna-Romero, Oscar, Rodrigues, Mauricio Martins [UNIFESP], Hoft, Daniel F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: https://dx.doi.org/10.1371/journal.pntd.0000983; https://repositorio.unifesp.br/handle/11600/33495

Background: Immunization of mice with the Trypanosoma cruzi trans-sialidase (TS) gene using plasmid DNA, adenoviral vector, and CpG-adjuvanted protein delivery has proven highly immunogenic and provides protection against acute lethal challenge. However, long-term protection induced by TS DNA vaccines has not been reported. the goal of the present work was to test whether the co-administration of a plasmid encoding IL-15 (pIL-15) could improve the duration of protection achieved through genetic vaccination with plasmid encoding TS (pTS) alone.Methodology: We immunized BALB/c mice with pTS in the presence or absence of pIL-15 and studied immune responses [with TS-specific IFN-gamma ELISPOT, serum IgG ELISAs, intracellular cytokine staining (IFN-gamma, TNF-alpha, and IL-2), tetramer staining, and CFSE dilution assays] and protection against lethal systemic challenge at 1 to 6 months post vaccination. Mice receiving pTS alone developed robust TS-specific IFN-gamma responses and survived a lethal challenge given within the first 3 months following immunization. the addition of pIL-15 to pTS vaccination did not significantly alter T cell responses or protection during this early post-vaccination period. However, mice vaccinated with both pTS and pIL-15 challenged 6 months post-vaccination were significantly more protected against lethal T. cruzi challenges than mice vaccinated with pTS alone (P<0.05). Improved protection correlated with significantly higher numbers of TS-specific IFN-gamma producing total and CD8(+) T cells detected >6 months post immunization. Also, these TS-specific T cells were better able to expand after in vitro restimulation.Conclusion: Addition of pIL-15 during genetic vaccination greatly improved long-term T cell survival, memory T cell expansion, and long-term protection against the important human parasite, T. cruzi.