Background. Research studies indicate that immunization with protein extracts of Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, prevents the appearance of tumors in 60% of mice injected with the murine lung carcinoma tumor line. The molecular basis of this process is unknown, although the presence of specific antigens in tumor cells and on the surface of T. cruzi suggests an antiparasitic immune response, with an effective cross-reaction against cancer cells, hence the importance to identify the antigens involved and determine their potential as target cells in anticancer therapy. Aim. This study aimed to determine the presence of antigenic proteins of T. cruzi shared with acute lymphoblastic leukemia and neuroblastoma cells. Material and methods. To achieve this, polyclonal antibodies against T. cruzi were developed in rabbits, and reactivity was determined with protein extracts of acute lymphoblastic leukemia cells and neuroblastoma. The immunodetection of five different strains of T. cruzi against anti-T. cruzi polyclonal antibodies was also performed. Conclusion. The study allows the knowledge of the immunological interactions between cancer and parasites to be expanded and, therefore, contributes to the design of more and better projects that improve the therapeutic strategies applied in oncology.

Parasites have been associated with possible anticancer activity, including Trypanosoma cruzi, which has been linked to inhibiting the growth of solid tumors. To better understand this antitumor effect, we investigated the association of anti-T. cruzi antibodies with B cells of the acute lymphoblastic leukemia (ALL) SUPB15 cell line. The antibodies were generated in rabbits. IgGs were purified by affinity chromatography. Two procedures (flow cytometry (CF) and Western blot(WB)) were employed to recognize anti-T. cruzi antibodies on SUPB15 cells. We also used CF to determine whether the anti-T. cruzi antibodies could suppress SUPB15 cells. The anti-T. cruzi antibodies recognized 35.5% of the surface antigens of SUPB15. The complement-dependent cytotoxicity (CDC) results demonstrate the cross-suppression of anti-T. cruzi antibodies on up to 8.4% of SUPB15 cells. For the WB analysis, a band at 100 kDa with high intensity was sequenced using mass spectrometry, identifying the protein as nucleolin. This protein may play a role in the antitumor effect on T. cruzi. The anti-T. cruzi antibodies represent promising polyclonal antibodies that have the effect of tumor-suppressive cross-linking on cancer cells, which should be further investigated.

It is little known that Acanthamoeba trophozoites and Toxocara canis eggs can reduce tumors in vitro and animal models. Although this has been known for many years, the mechanism that induces the antitumor effect in these parasites is still not known. We employed Western blot (WB) and immunofluorescence (IFC) by confocal microscopy to explore the potential protein binding between neuroblastoma (NB) SH-SY5Y cells and anti-Acanthamoeba and anti-Toxocara canis antibodies. Using WB, we detected two fragments of 70 kDa and 60 kDa recognized by the anti-Acanthamoeba antibodies, and two fragments of 115 kDa and 70 kDa recognized by the anti-Toxocara canis antibodies. In both cases, the IFC results were positive in the cell membrane of the SH-SY5Y cells. Our findings suggest a potential overlap of similar molecules between these parasites and tumor cells, which may contribute to tumor elimination. Investigating the relationship between anti-Acanthamoeba and anti-Toxocara canis antibodies in neoplastic cells could provide evidence for the future use of these anti-parasitic antibodies in targeting NB or other cancers.