Combination of live attenuatted Trypanosoma cruzi parasites with IFN-ƍ expressing plasmid as an immunization strategy

CECILIA PÉREZ BRANDÁN; FERNANDO SÁNCHEZ VALDÉZ; RUBÉN CIMINO; DIOSQUE PATRICIO; BASOMBRÍO MIGUEL ANGEL

Mar del Plata

Congreso; X Congreso de Protozoología y Enfermedades parasitarias; 2014

Sociedad Argentina de Protozoología

Immunization of mice with live attenuated Trypanosoma cruzi parasites has proven highlyimmunogenic and protective against acute lethal challenge. It is known that earlyinterferon-gamma (IFN-γ) release by cells of the innate immune system is critical to leadtype 1 response able to control intracellular pathogens. Therefore, the aim of the presentwork is to test whether the co-administration of a plasmid encoding IFN-γ could improvethe protection gain through vaccination with live attenuated parasites. For this purposeC57BL/6J mice were immunized with three doses of 5x105 live metacyclic parasites incombination with 50ug of plasmid pCDNA3- IFN-γ or plasmid alone. The immunizationregimens were done every 4 weeks either orally or intramuscularly. Thirty days after thelast immunization, animals were challenge with highly virulent T. cruzi parasites andparasitemia was recorded weekly. During the immunization period, peripheral blood wastaken to determine infection by attenuated parasites. Serum samples as well as spleencells were collected to determined cytokines expression. Specific anti-T. cruzi antibodies,avidity index and trypanolitic activity was also evaluated in immunized sera. All immunizedanimals survive challenge with lethal parasites. So far, addition of IFN-γ, at least asadminister in our experimental model, does not modified the protection confer byimmunization with attenuated parasites alone