Tumor-Suppressive Cross-Linking of Anti-T. cruzi Antibodies in Acute Lymphoblastic Leukemia.

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.

The MAK16 gene of Entamoeba histolytica and its identification in isolates from patients.

To identify sequences of Entamoeba histolytica associated with the development of amebic liver abscess (ALA) in hamsters, subtractive hybridization of cDNA from E. histolytica HM-1:IMSS under 2 growth conditions was performed: 1) cultured in axenic medium and 2) isolated from experimental ALA in hamsters. For this procedure, 6 sequences were obtained. Of these sequences, the mak16 gene was selected for amplification in 29 cultures of E. histolytica isolated from the feces of 10 patients with intestinal symptoms and 19 asymptomatic patients. Only 5 of the 10 isolates obtained from symptomatic patients developed ALA and amplified the mak16 gene, whereas the 19 isolates from asymptomatic patients did not amplify the mak16 gene nor did they develop ALA. Based on the results of Fisher's exact test (P<0.001), an association was inferred between the presence of the mak16 gene of E. histolytica and the ability to develop ALA in hamsters and with the patient's symptoms (P=0.02). The amplification of the mak16 gene suggests that it is an important gene in E. histolytica because it was present in the isolates from hamsters that developed liver damage.

Trypanosoma cruzi Antigenic Proteins Shared with Acute Lymphoblastic Leukemia and Neuroblastoma.

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.

Co-infection of Dengue, Zika and Chikungunya in a group of pregnant women from Tuxtla Gutiérrez, Chiapas: Preliminary data. 2019.

INTRODUCTION: Dengue, Zika and Chikungunya are RNA Arboviruses present in some areas of Mexico, mainly in the endemic state of Chiapas that is characterized by presence of the vector that transmit them and an ecology that favors high transmission. According to the national epidemiological surveillance system, Dengue has intensified since 2018 and outbreaks continue in various states while for Zika and Chikungunya a decrease in cases has been reported in recent years. The main objective of this study was to determine the incidence of Dengue, Zika and Chikungunya infections during pregnancy in the state of Chiapas. PRINCIPAL FINDINGS: The presence of previous and current infections and coinfections diagnosed by molecular (RT-PCR) and immunological (ELISA for IgG determination) techniques indicates a wide circulation of viruses in asymptomatic people, specifically in pregnant women showing that silent infections in dry season contributes to the preservation of viruses. CONCLUSIONS: From 136 studied samples, 27.7% tested positive for DENV, 8% for ZIKV and 24.1% for CHIKV by RTPCR and the values of IgG in sera show that 83.9% were positive for IgG antibodies against DENV, 65% against ZIKV and 59.1% against CHIKV. Results demonstrated presence of ZIKV and CHIKV, not detected by the epidemiological surveillance system, so the importance of establishing proactive epidemiological systems more strict, especially because these infections in pregnant women can cause severe health problems for newborn children.

Infectious Agents in Childhood Leukemia.

Acute leukemia is the most common pediatric cancer, representing one-third of all cancers that occurs in under 15 year olds, with a varied incidence worldwide. Although a number of advances have increased the knowledge of leukemia pathophysiology, its etiology remains less well understood. The role of infectious agents, such as viruses, bacteria, or parasites, in the pathogenesis of leukemia has been discussed. To date, several cellular mechanisms involving infectious agents have been proposed to cause leukemia following infections. However, although leukemia can be triggered by contact with such agents, they can also be beneficial in developing immune stimulation and protection despite the risk of leukemic clones. In this review, we analyze the proposed hypotheses concerning how infectious agents may play a role in the origin and development of leukemia, as well as in a possible mechanism of protection following infections. We review reported clinical observations associated with vaccination or breastfeeding, that support hypotheses such as early life exposure and the resulting early immune stimulation that lead to protection.

Entamoeba histolytica sequences and their relationship with experimental liver abscesses in hamsters.

The purpose of the present paper was to analyse the association between sequences of Entamoeba histolytica and their relationship with the development of hepatic abscesses in hamsters, using a complementary DNA library for E. histolytica. From the sequences obtained, we designed oligonucleotides for amplification by PCR. Trophozoites were isolated from faeces of 11 patients in whom cysts from E. histolytica were identified, and these trophozoites were then subjected to monoaxenic culture. Then 1 x 10(5) trophozoites were inoculated into hamster liver, with three hamsters used for every culture. Sequences were obtained for ubiquitin, lectin surface precursor, replication factor MCM3 and surface antigen. The associations between sequences and hepatic abscesses were: 11/11 for ubiquitin, 9/11 for lectin precursor, 4/11 for replication factor and 1/11 for surface antigen. These results suggest that ubiquitin could be an important protein involved in the mechanism of E. histolytica invasion.

Efecto in vitro de prazicuantel sobre la actividad de Giardia intestinalis / In vitro effects of praziquantel over the trophozoites of Giardia intestinalis

Se realizó un estudio in vitro para conocer el efecto farmacológico de prazicuantel sobre los trofozoítos de Giardia intestinalis cepa P-1. Después de cultivarlos axénicamente, con cinco diferentes concentraciones de prazicuantel (de 0.32 hasta 1.62 nM/mL) durante 24 h a 37ºC, la viabilidad y la CI50 evaluada por la captación de colorante fluorogénico con citometría de flujo mostró un desplazamiento logarítmico de 10º a 10 a la tercera lo que correspondió a una concentración de 1.28 nM/mL. La incorporación de H3 metil-timidina como parámetro de crecimiento celular a 50 por ciento alcanzó 1.20 nM/mL de prazicuantel y el efecto citotóxico calculado por la capacidad de lisar células CHO (células de ovario de hámster chino) marcados con Cr51 se observó para la CI50 en una concentración de 1.05 nM/mL. Con estos tres parámetros se puede inferir qué viabilidad a 50 por ciento se observó a concentraciones más altas de prazicuantel comparadas con la capacidad para dividirse, así como el efecto citolítico, en donde la concentraciones más altas de prazicuantel comparadas con la capacidad para dividirse, así como el efecto citolítico, en donde la concentración de prazicuantel fue la más baja a lo que se atribuye la cualidad de apagar radicales libres, sin embargo, esto no fue proporcional al incrementar la concentración suponiéndose una importante capacidad detoxificante en Giardia. Se concluye que prazicuantel desarrolló actividad farmacológica en protozoarios, lo que le hace susceptible de emplearse contra la giardiasis