Joel Martinez-Ocaña

Induction of Protection against Porcine Cysticercosis by Vaccination with Recombinant Oncosphere Antigens

ABSTRACT Two recombinant Taenia solium oncosphere antigens, designated TSOL18 and TSOL45-1A, were investigated as vaccines to prevent transmission of the zoonotic disease cysticercosis through pigs. Both antigens were effective in inducing very high levels of protection (up to 100%) in three independent vaccine trials in pigs against experimental challenge infection with T. solium eggs, which were undertaken in Mexico and Cameroon. This is the highest level of protection that has been achieved against T. solium infection in pigs by vaccination with a defined antigen. TSOL18 and TSOL45-1A provide the basis for development of a highly effective practical vaccine that could assist in the control and, potentially, the eradication of human neurocysticercosis.

Antibody responses and epitope specificities to the Taenia solium cysticercosis vaccines TSOL18 and TSOL45-1A

Taenia solium is a cestode parasite that causes cysticercosis in humans and pigs. This study examined the antibody responses in pigs immunized with the TSOL18 and TSOL45‐1A recombinant vaccines against T. solium cysticercosis. Immunization with these proteins induced specific, complement‐fixing antibodies against the recombinant antigens that are believed to be associated with vaccine‐induced protection against T. solium infection. Sera from immunized pigs were used to define the linear B‐cell epitopes of TSOL18 and TSOL45‐1A. Prominent reactivity was revealed to one linear epitope on TSOL18 and two linear epitopes on TSOL45‐1A. These, and oncosphere antigens from other taeniid cestodes, contain a protein sequence motif suggesting that they may show a tertiary structure similar to the fibronectin type III domain (FnIII). Comparison of the location of linear antigenic epitopes in TSOL18 and TSOL45‐1A within the proposed FnIII structure to those within related cestode vaccine antigens reveals conservation in the positioning of the epitopes between oncosphere antigens from different taeniid species.

Cloning, Characterization, and Functional Expression of Taenia Solium Calreticulin

Calreticulin is an endoplasmic reticulum protein involved in the homeostasis of intracellular Ca++ and other physiological processes. A complementary DNA clone containing the complete coding sequence of Taenia solium calreticulin (TsCRT) was isolated and characterized. Recombinant TsCRT was expressed in bacteria as a 50-kDa protein that specifically bound calcium when tested in a radioassay. The deduced amino acid sequence has 47–50% identity with other reported calreticulins. Poor recognition of TsCRT by human and pig sera with confirmed cysticercosis discourages its use for diagnosis of the disease. However, further characterization and localization studies could provide insights into the role of TsCRT in T. solium physiology and host–parasite interactions.

Plasma cytokine levels and cytokine gene polymorphisms in Mexican patients during the influenza pandemic A(H1N1)pdm09

BACKGROUND In Mexico, the initial severe cases of the 2009 influenza pandemic virus A (H1N1) [A(H1N1)pdm09] were detected in early March. The immune mechanisms associated with the severe pneumonia caused by infection with this new virus have not been completely elucidated. Polymorphisms in interleukin genes have previously been associated with susceptibility to infectious diseases due to their influence on cytokine production. OBJECTIVES The present case-control study was performed to compare several immunologic and genetic parameters of patients and controls during the initial phase of the pandemic. STUDY DESIGN Sixty-five patients who were hospitalized due to infection with the influenza A(H1N1)pdm09 virus and 46 healthy controls were studied. A hemagglutination inhibition assay (HIA) was performed to measure anti-influenza antibody titers in these subjects. Protein levels of the cytokines interleukin (IL)-4, IL-6, IL-8, IL-10, tumor necrosis factor-α (TNFα), interferon gamma (IFNγ), transforming growth factor beta (TGFβ)1 and TGFβ2 were quantified in plasma. Single nucleotide polymorphisms in IL6, IL10 and TNFα were also assessed. RESULTS Influenza patients had lower antibody titers and produced significantly higher levels of IL-6, IL-10 and TNFα than healthy controls. The frequencies of the TNFα -308G, IL-10 -592C and IL-10 -1082A alleles and the IL10 -1082(A/A) genotype were associated with susceptibility to severe disease, while the haplotypes TNFα AG and IL-10 GTA and GCA were associated with protection from severe disease [P=0.016, OR (CI)=0.11 (0.01-0.96); P=0.0187, OR (CI)=0.34 (0.13-0.85); P=0.013, OR (CI)=0.39 (0.18-0.83)]. CONCLUSIONS This study demonstrates that the influenza A(H1N1)pdm09 patients and healthy controls have different profiles of immune parameters and that there is an association between IL-10 and TNFα polymorphisms and the outcome of this disease.

Blastocystis Isolates from Patients with Irritable Bowel Syndrome and from Asymptomatic Carriers Exhibit Similar Parasitological Loads, but Significantly Different Generation Times and Genetic Variability across Multiple Subtypes

Blastocystis spp is a common intestinal parasite of humans and animals that has been associated to the etiology of irritable bowel syndrome (IBS); however, some studies have not found this association. Furthermore, many biological features of Blastocystis are little known. The objective of present study was to assess the generation times of Blastocystis cultures, from IBS patients and from asymptomatic carriers. A total of 100 isolates were obtained from 50 IBS patients and from 50 asymptomatic carriers. Up to 50 mg of feces from each participant were cultured in Barret’s and in Pavlova’s media during 48 h. Initial and final parasitological load were measured by microscopy and by quantitative PCR. Amplicons were purified, sequenced and submitted to GenBank; sequences were analysed for genetic diversity and a Bayesian inference allowed identifying genetic subtypes (ST). Generation times for Blastocystis isolates in both media, based on microscopic measures and molecular assays, were calculated. The clinical symptoms of IBS patients and distribution of Blastocystis ST 1, 2 and 3 in both groups was comparable to previous reports. Interestingly, the group of cases showed scarce mean nucleotide diversity (π) as compared to the control group (0.011±0.016 and 0.118±0.177, respectively), whilst high gene flow and small genetic differentiation indexes between different ST were found. Besides, Tajima’s D test showed negative values for ST1-ST3. No statistical differences regarding parasitological load between cases and controls in both media, as searched by microscopy and by qPCR, were detected except that parasites grew faster in Barret’s than in Pavlova’s medium. Interestingly, slow growth of isolates recovered from cases in comparison to those of controls was observed (p<0.05). We propose that generation times of Blastocystis might be easily affected by intestinal environmental changes due to IBS probably because virulent strains with slow growth may be selected, reducing their genetic variability.

Immunolocalization of TSOL18 and TSOL45-1A, the successful protective peptides against porcine cysticercosis, in Taenia solium oncospheres

Taenia solium life cycle includes humans as definitive hosts and pigs as intermediate hosts. One of the measures to stop the life cycle of this parasite is by vaccination of pigs. In experiments performed in pigs with TSOL18 and TSOL45-1A, two recombinant T. solium proteins, 99.5% and 97.0% protection was induced, respectively. The purpose of this paper was to localize these antigens in all stages of the parasite (adult worms, oncospheres and cysticerci) by immunofluorescence, with the use of antibodies against TSOL18 and TSOL45-1A that were obtained from the pigs used in the vaccination experiment. Results show that TSOL18 and TSOL45-1A are expressed on the surface of T. solium oncospheres and not in tapeworms or cysticerci, indicating that they are stage-specific antigens. This, therefore, might explain the high level of protection these antigens induce against pig cysticercosis.

Comparison of hemodynamic, biochemical and hematological parameters of healthy pregnant women in the third trimester of pregnancy and the active labor phase

BackgroundPregnancy is accompanied by several hemodynamic, biochemical and hematological changes which revert to normal values after labor. The mean values of these parameters have been reported for developed countries, but not for Mexican women. Furthermore, labor constitutes a stress situation, in which these factors may be altered. It is known that serologic increase of heat shock protein (Hsp) 70 is associated with abnormal pregnancies, presenting very low level in normal pregnant women. Nevertheless, there are no studies where these measurements are compared in healthy pregnant women at their third trimester of pregnancy (3TP) and the active labor phase (ActLP).MethodsSeventy five healthy Mexican pregnant women were included. Hemodynamic, biochemical and hematological parameters were obtained in all cases, and serum Hsp70 levels were measured in a sample of 15 women at 3TP and at ActLP.ResultsSignificant differences were found in most analysis performed and in Hsp70 concentration at 3TP as compared to ActLP, however all were within normal range in both conditions, supporting that only in pathological pregnancies Hsp70 is drastically increased.ConclusionResults obtained indicate that 3TP and ActLP have clinical similarities in normal pregnancies, therefore if abnormalities are found during 3TP, precautions should be taken before ActLP.

Identification of opportunistic parasites and helminth ova in concentrated water samples using a hollow-fibre ultrafiltration system

In the present study, we applied an ultrafiltration process to detect Blastocystis spp., Cryptosporidium parvum, Giardia lamblia and helminth ova during a dry season with cold and warm periods. Samples of wastewater, reuse water for the irrigation of green areas and groundwater were collected on the campus of the National Autonomous University of Mexico. Physicochemical parameters were measured. Blastocystis spp. and its subtypes (ST) were identified using polymerase chain reaction (PCR) and indirect immunofluorescence (IFA); G. lamblia and C. parvum were identified using IFA, and helminth ova were searched for using flotation/sedimentation and microscopic observation. Blastocystis ST3, C. parvum and G. lamblia were detected in wastewater and reuse water, but only G. lamblia was detected in all of the samples of reuse water. Helminth ova were not detected. Statistical analysis showed a dependency between total dissolved solids and protozoa. Our data suggest that G. lamblia detection can be performed as part of reuse water quality assessments for irrigation systems.