Potential of baculovirus as expression and delivery system of heterologous antigens of Trypanosoma cruzi in immunization assays

MASIP, Y; MOLINA, G; CAEIRO, L; TABOGA, OA; SANCHEZ, DO; MOLINARI, MP; TEKIEL, V.

Mar del Plata

Congreso; LXVI Reunión Anual de la Sociedad Argentina de Inmunología. Reunión conjunta SAIC-SAI-SAFIS, 14-17 noviembre 2018.; 2018

SAI- SAIC- SAFI

Potential of baculovirus as expression and delivery system of heterologous antigens of Trypanosoma cruzi in immunization assays. Trypanosoma cruzi, the etiological agent of Chagas disease, has intracellular (amastigote) and extracellular (trypomastigote) stages in the vertebrate host. TcTASV is a multigenic family unique to T. cruzi present in all strains of the parasite analyzed so far and expressed in parasite stages infecting the mammalian host. Subfamilies TcTASV-A and TcTASV-C are the most numerous and have differential expression: TcTASV-A is expressed intracellularly in amastigotes/ trypomastigotes while TcTASV-C is expressed at trypomastigote surface and secreted (Garcia et al, 2010; Bernabó et al, 2013; Caeiro et al, 2018). A previous prime-boost vaccination assay with TcTASV-C (DNA/protein) delayed the time of appearance of bloodstream trypomastigotes and partially improved the infection outcome in challenged mice, which was mediated by a humoral response directed to the TcTASV protein motif (Caeiro et al, 2018). We hypothesize that the efficacy of the vaccination protocol could be improved summing a cellular immune response against an intracellular antigen, like TcTASV-A. The baculovirus (BV) system is a promising platform for vaccine delivery that elicit potent cytotoxic immune response when antigens are displayed at the capsid. Hence, we engineered a recombinant baculovirus expressing TcTASV-A fused to the major nucleocapsid protein VP39 (BV-TcTASV-A). Expression of VP39-TcTASV-A was confirmed by Western blot and immunofluorescence. C3H/He mice were immunized by a first dose of rTcTASV-C (25µg) adjuvanted with aluminium hydroxide, followed by a boost with BV-TcTASV-A (1.107 PFU) plus rTcTASV-C (25µg) 21 days later. Mice immunized with TcTASVs elicited a strong anti-TcTASV-C humoral response (title>1/204800). Intracytoplasmic cytokines measured by flow cytometry evidenced differential CD8+/IFNγ+ and CD4+/IFNγ+ populations after stimulation with TcTASV-A (5,2%) and TcTASV-C (0.7%), respectively (p