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

MASIP, YAMIL E.; CAEIRO, LUCAS D.; MOLINA, GUIDO; TABOGA, OSCAR; SÁNCHEZ, DANIEL O.; MOLINARI, MARÍA P.; TEKIEL, VALERIA

Mar del Plata

Congreso; LXVI Reunión Anual de la Sociedad Argentina de Inmunología; 2018

Sociedad Argentina de Inmunología

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 (1.10 7 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 stimulationwith TcTASV-A (5,2%) and TcTASV-C (0.7%), respectively (p