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.

Visceral larva migrans syndrome (VLM) is caused by L2 Toxocara canis. This parasitic disease is difficult to diagnose in humans, but specific antigen identification could allow for parasite detection. The aim of this study was to analyse antigens of different parasite developmental stages and observe their cross-reactions with antigens from other parasites to determine their importance in the diagnosis of VLM caused by T. canis. Sera from 14 children with cryptogenic epilepsy previously positive for T. canis were analysed via Western blot (WB) using T. canis excretion-secretion antigens (TESs) from distinct morphological parasite stages; cross-reactivity of these antigens with antigens from other parasites were evaluated. Children sera recognized antigens from L2 T. canis TES, mainly a protein of 24 kDa. Proteins in the medium- and high-molecular-weight ranges were also detected in the egg phase. In the adult phase, only 42.9% of analysed sera recognized a protein of high-molecular weight. Cross-reaction tests identified medium and high-molecular weight proteins, mainly from L2 of Ascaris lumbricoides and Gnathostoma binucleatum and adults of Ancylostoma caninum, but none of the proteins found had crossover with low-molecular weight proteins from Toxocara canis. Antigens in the larval morphological stage of T. canis TES were recognized in the highest percentage of the analysed sera; these antigens could be used to diagnose VLM.