ENGINEERED BACTERIAL OUTER MEMBRANE VESICLES AS AN EXPERIMENTAL VACCINE AGAINST CHAGAS DISEASE

PÉREZ BRANDAN, CECILIA; ACUÑA, LEANDRO; MESÍAS, ANDREA; SÁNCHEZ VALDEZ, FERNANDO; PARODI, CECILIA; WALPER, SCOTT

Parana

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2018

SAIB

Outer membrane vesicles (OMVs) are nanoparticles released from bacteria. Three of the most promising characteristics of OMVs are their highadjuvant capacity, their safety and the possibility of generating genetically engineered vesicles. Therefore, the utilization of OMVs as vaccinesoffers promising potential against a wide range of diseases. With this in mind we proposed to evaluate the potential role of engineered OMVscarrying different Trypanosoma cruzi antigens as an experimental immunogen against Chagas disease. We selected two antigens which havebeen extensively evaluated in vaccination models against T. cruzi, Tc24 and Tc52. The rational of selecting these antigens is that as a first stepwe propose to elucidate the advantage of using OMVs as carriers of parasite antigens and evaluate their adjuvant properties. As the first timereported, we were able to obtain recombinant OMVs with the selected T. cruzi antigens expressed on the outside of the vesicles as well aspackaged within their lumen. These rOMVs were preliminarily evaluated in a murine prime-boot-challenge scheme for Chagas disease. Duringthe vaccination stage, a slight increase in IFN-gamma production was detected in immunized animals. In the challenge phase, a mild decrease inparasite load in vaccinated animals versus control groups could be detected. Several factors still need to be tested in order to optimize the use of rOMVs as a possible vaccine. In summary, the results so far obtained indicate that genetically designed OMVs could be a possible path for thedevelopment of novel strategies for trypanosomatids immunization.