Assessment of new adjuvants formulations with the protein Transialidase to achieve immunoprotection against Trypanosoma cruzi infection

IVÁN BONTEMPI, MIGUEL VICCO1, GABRIEL CABRERA1, SILVINA VILLAR 2, ANA ROSA PEREZ2, IVÁN MARCIPAR1

Seattle

Congreso; The Models of action of vaccine Adjuvants; 2014

Chagas disease is a major public health of Latin American caused by the protozoan parasite, Trypanosoma cruzi (T. cruzi). In this work, we assess the recombinant enzyme from T. cruzi, Transialidase (TS) with a new formulation using a human potentially applicable adjuvant, the immunostimulatory ISCOMATRIX (IMX). We inoculated groups of BALB/c mice with: TS-IMX (10 ug TS and 5 ug IMX); TS-FA (10ug TS in 50 ul with 50 ul Freund´s Adjuvant); TS (10 ug of TS, without adjuvant) or PBS (control group). High levels of specific anti-TS antibodies had been developed after the third inoculation in all iTS-immunized groups (P <0.01 vs. preimmune, Mann-Whitney). The ratio IgG2a/igG1 was upper 1 only for TS-IMX group indicating a Th1 profile. The Delayed-type hypersensitivity (DTH) with TS was performed to compare the cellular response between groups. Only iTS-IMX had significant difference with the control groups (P<0,05 vs PBS; Dunn).  Fifteen days after the last immunization, mice were challenged with 1000 parasites and monitored for 100 days. Parasitemia was measured in all groups every 15 days being significantly lower in TS-IMX throughout the period (P< 0,01 vs. PBS; Dunn). All mice of TS-IMX group survived all along the experiment (P <0.05, iTS-IMX vs. control; Mantel-Cox), whereas other groups had non-significant differences in relation to control group (P>0,05, Mantel-Cox). The ability of ISCOMATRIX adjuvant to switch the immune profile from susceptibility to protection is discussed.