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

BULFONI BALBI C,; FARRÉ C, ; PACINI MF,; GONZÁLEZ F, R; VILLAR S, ; CHAPO G, ; MARCIPAR I, ; MENACHO MÁRQUEZ M,; ALLOATTI, A; PÉREZ ANA ROSA

Tucumán

Congreso; LXVII Reunión científica anual de la Sociedad Argentina de Inmunología; 2019

Anti-tumor activity of parasites, such as Trypanosoma cruzi (Tc), has been reported in both experimental 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 of parasitic molecules with anti-tumoral properties may explain these findings. Here, we analyze if antigen extracts derived from Tc have a prophylactic effect on tumor growth and metastasis development. For this, antigenic lysates (Ag, 2 mg/mL) were emulsified in ISPA (ISCOMATRIX-like adjuvant) or in PBS. Other groups of mice were treated with ISPA or PBS alone. BALB/c female mice (n=5-6) were inoculated subcutaneously with these formulations (3 doses, one every 15 days). Fifteen days after the last immunization, 5.104 4T1 tumor cells were implanted subcutaneously on the opposite flank. To assess the anti-tumor effect, the tumor volume was recorded every 3 days using a digital caliper. After 24 days, mice were sacrificed and primary tumors were weighed and fixed, while lungs were removed for metastatic evaluation. Ag+ISPA significantly suppressed tumor growth, while ISPA alone showed a similar tendency. Likewise, Ag+ISPA decrease the proportion of lung metastases on a macroscopic scale. By immunohistochemistry and immunofluorescence, we demonstrated that anti-Tc antibodies are capable of recognizing epitopes in 4T1 tumors. These findings suggest that when Tc extracts formulated with ISPA were administered prophylactically had anti-tumoral effects.