PROPHYLACTIC IMMUNIZATION WITH PARASITE-DERIVED ANTIGENS DECREASES THE GROWTH OF A MAMMARY TUMOR IN MICE

PACINI MF; CHAPO G; ALLOATTI A; BULFONI BALBI C ; GONZÁLEZ F ; MARCIPAR I ; PEREZ AR; FARRÉ C ; VILLAR S ; MENACHO MÁRQUEZ M

Tucuman

Congreso; LXVII Reunion Anual de la SAI; 2019

Sociedad Argentina de Inmunologia

Anti-tumor activity of parasites, such as Trypanosoma cruzi (Tc), has been reported in bothexperimental and clinical scenarios. The bases of this anti-tumoral response are still unknown,but the occurrence of common antigens in tumors and parasites, and/or the presence ofparasitic molecules with anti-tumoral properties may explain these findings. Here, we analyze ifantigen extracts derived from Tc have a prophylactic effect on tumor growth and metastasisdevelopment. For this, antigenic lysates (Ag, 2 mg/mL) were emulsified in ISPA (ISCOMATRIXlikeadjuvant) or in PBS. Other groups of mice were treated with ISPA or PBS alone. BALB/cfemale mice (n=5-6) were inoculated subcutaneously with these formulations (3 doses, oneevery 15 days). Fifteen days after the last immunization, 5.104 4T1 tumor cells were implantedsubcutaneously on the opposite flank. To assess the anti-tumor effect, the tumor volume wasrecorded every 3 days using a digital caliper. After 24 days, mice were sacrificed and primarytumors were weighed and fixed, while lungs were removed for metastatic evaluation. Ag+ISPAsignificantly suppressed tumor growth, while ISPA alone showed a similar tendency. Likewise,Ag+ISPA decrease the proportion of lung metastases on a macroscopic scale. Byimmunohistochemistry and immunofluorescence, we demonstrated that anti-Tc antibodies arecapable of recognizing epitopes in 4T1 tumors. These findings suggest that when Tc extractsformulated with ISPA were administered prophylactically had anti-tumoral effects.