Cytokines are highly inducible, secretory proteins that mediate intercellular communication in the immune system. They are grouped into several protein families that are referred to as tumor necrosis factors, interleukins, interferons, and colony-stimulating factors. In recent years, it has become clear that some of these proteins as well as their receptors are produced in the organisms under physiological and pathological conditions. The exact initiation process of breast cancer is unknown, although several hypotheses have emerged. Inflammation has been proposed as an important player in tumor initiation, promotion, angiogenesis, and metastasis, all phenomena in which cytokines are prominent players. The data here suggest that cytokines play an important role in the regulation of both induction and protection in breast cancer. This knowledge could be fundamental for the proposal of new therapeutic approaches to particularly breast cancer and other cancerrelated disorders.

The amino acid sequence of triosephosphate isomerase from Trypanosoma brucei, Trypanosoma cruzi, and Leishmania mexicana have an identity of 68%. Using the numbering system for the T. brucei enzyme, in their aligned sequences, the T. cruzi and leishmanial enzymes have cysteine residues at positions 14, 40, 117 and 126. T. brucei triosephosphate isomerase has cysteine residues at positions 14, 40 and 126, and a valine residue at position 117. Dithionitrobenzoic acid and methylmethane thiosulfonate inhibited the three enzymes, but T. cruzi triosephosphate isomerase was more than 100-fold more sensitive. The sensitivity of wild type triosephosphate isomerase from T. cruzi and T. brucei to the reagents was equal to that of the Cys117Val and Val117Cys mutant enzymes, respectively. Triosephosphate isomerases that have cysteine residues at positions 40 and 126, but lack a cysteine residue at position 14 are insensitive to methylmethane thiosulfonate. Thus, sulfhydryl reagents act on Cys14. At stoichiometric concentrations, the reagents inhibited the three enzymes as a consequence of structural alterations as measured by binding of 8-anilino-1-napthalenesulfonic acid to previously buried hydrophobic regions. However, the times for half-maximal alterations were 10 min, 15 hours and over 30 hours for T. cruzi, T. brucei and L. mexicana triosephosphate isomerase, respectively. The effect of pH on the action of the sulfhydryl reagents and molecular modeling showed no differences in the solvent accesibility of Cys14. As Cys14 forms part of the dimer interface, the data indicate that, in the three enzymes, barriers of different magnitude hinder the interaction between the sulfhydryl reagents and Cys14. The barrier is lower in T. cruzi triosephosphate isomerase which makes its dimer interface more susceptible for perturbation.Keywords : triosephosphate isomerase; trypanosome ; cysteine residue; protein conformations; protein changes.Triosephosphate isomerase is a homodimeric enzyme whose activity. Some attempts have been made with this target in mind kinetics [1] and structure [2Ϫ8] are well established. It is the [20]. prototype of an A-β barrel and thus, this enzyme has been extenOur group has worked on the hypothesis that nonconserved sively studied with respect to the relation that exists between its amino acids that are central for stability or catalysis can be structure and function [9Ϫ11]. It is also noteworthy that excellent targets for achieving species-specific inhibition of triosephosphate isomerase has been considered a potential target homologous enzymes [21]. Through site-directed mutagenesis for drug design against pathogenic parasites [12Ϫ14] ; the latter and chemical-modification studies, we found that the integrity studies have focused on the active center of the enzyme. Studies of the nonconserved Cys14 of triosephosphate isomerase from on the reactivation of triosephosphate isomerase from denatured Trypanosoma brucei is fundamental for maintaining its structure triosephosphate isomerase monomers [15Ϫ17] ha...

The gene that encodes for triosephosphate isomerase froin Trypanosoma cruzi was cloned and sequenced. In 7: cruzi, there is only one gene for triosephosphate isomerase. The enzyme has an identity of 12% and 68 5% with triosephosphate isomerase from Trypanosoma brucei and Leishmania mexicanu, respectively. The active site residues are conserved: out of the 32 residues that conform the interface of dimeric triosephosphate isomerase from 7: brucei, 29 are conserved in the 7: cruzi enzyme. The enzyme was expressed in Escherichia coli and purified to homogeneity. Data from electrophoretic analysis under denaturing techniques and filtration techniques showed that triosephosphate isomerase from 7: cruzi is a homodimer. Some of its structural and kinetic features were determined and compared to those of the purified enzymes from 7: brucei and L. mexicana. Its circular dichroism spectrum was almost identical to that of triosephosphate isomerase from 7: brucei. Its kinetic properties and pH optima were similar to those of ' I: brucei and L. mexicana, although the latter exhibited a higher V,,,, with glyceraldehyde 3-phosphate as substrate. The sensitivity of the three enzymes to the sulfhydryl reagent methylmethane thiosulfonate (MeS0,-SMe) was determined; the sensitivity of the 7: cruzi enzyme was about 40 times and 200 times higher than that of the enzymes from 7: brucei and L. mexicana, respectively. Triosephosphate isomerase from 7: cruzi and L. mexicana have the three cysteine residues that exist in the ' I : brucei enzyme (positiuns 14, 39, 126, using the numbering of the 7: brucei enzyme); however, they also have an additional residue (position 1 1 7). These data suggest that regardless of the high identity of the three trypanosomatid enzymes, there are structural differences in the disposition of their cysteine residues that account for their different sensitivity to the sulthydryl reagent. The disposition of the cysteine in triosephosphate isomerase from 7: cr~17i appears to make it unique for inhibition by modification of its cysteine.

For early detection of cancer, education and screening are important, but the most critical factor is the development of early diagnostic tools. Methods that recognize the warning signs of cancer and take prompt action lead to an early diagnosis; simple tests can identify individuals in a healthy population who have the disease but have not developed symptoms. Early detection of cancer is significant and is one of the most promising approaches by which to reduce the growing cancer burden and guide curative treatment. The early diagnosis of patients with breast cancer is challenging, since it is the most common cancer in women worldwide. Despite the advent of mammography in screening for breast cancer, low-resource, low-cost alternative tools must be implemented to complement mammography findings. IgM is part of the first line of defense of an organism and is responsible for recognizing and eliminating infectious particles and removing transformed cells. Most studies on breast cancer have focused on the development of IgG-like molecules as biomarkers or as a treatment for the advanced stages of cancer, but autoantibodies (IgM) and tumor-associated antigens (proteins or carbohydrates with aberrant structures) have not been examined as early diagnostic tools for breast cancer. The present review summarizes the function of natural and adaptive IgM in eliminating cancer cells in the early stages of pathology and their value as early diagnostic tools. IgM, as a component of the immune system, is being used to identify tumor-associated antigens and tumor-associated carbohydrate antigens.

Taenia solium cysticercosis is a health problem in underdeveloped and developed countries. Sex hormones are involved in cysticercosis prevalence in female and male pigs. Here, we evaluated the effects of progesterone and its antagonist RU486 on scolex evagination, which is the initial step in the development of the adult worm. Interestingly, progesterone increased T. solium scolex evagination and worm growth, in a concentration-independent pattern. Progesterone effects could be mediated by a novel T. solium progesterone receptor (TsPR), since RU486 inhibits both scolex evagination and worm development induced by progesterone. Using RT-PCR and western blot, sequences related to progesterone receptor were detected in the parasite. A phylogenetic analysis reveals that TsPR is highly related to fish and amphibian progesterone receptors, whereas it has a distant relation with birds and mammals. Conclusively, progesterone directly acts upon T. solium cysticerci, possibly through its binding to a progesterone receptor synthesized by the parasite.

No abstract

Amoebiasis is caused by the protozoa Entamoeba histolytica and persists as one of the leading parasitic diseases affecting millions worldwide. This parasite invades the intestinal mucosa, causing amoebic colitis and ulcers. It may also spread to other organs, mainly the liver, causing amoebic liver abscess (ALA). Current research efforts have focused on the development of specific diagnostic tests and animal models searching for a better understanding of the complex physiopathology of this disease. Analysis of the inflammatory immune response during intestinal amoebiasis in both human disease and animal murine models has revealed an important regulatory role for chemokines and cytokines. Recruitment and activation of inflammatory cells can also be modulated by specific protease-mediated cleavage of cytokines and by secreted amoebic factors such as amoebapores and monocyte locomotion inhibitory factor (MLIF). Unlike intestinal amoebiasis, analysis of the immune response in ALA has mainly been done in the hamster model. This has limited our information regarding the immune response during this phase of the disease. However, even with these limitations, several Th1/2 cytokines, such as IL-6 and IL-4, and regulatory cytokines, like IL-10 and TGFbeta, have been associated to the development of this disease.

A plasmid vector carrying the immunoprotective amino-terminal fragment of Taenia solium paramyosin (VW2-1) was designed for genetic vaccination studies. Mice that were genetically immunized with VW2-1 and challenged by intraperitoneal inoculation of Taenia crassiceps cysticerci showed 43 to 48% reductions in the parasite burden, values which were similar to values obtained previously when the recombinant protein was used.Human and porcine cysticercosis caused by Taenia solium is still prevalent in several countries of Latin America, Africa, and Asia (11). A strong effort is currently being directed toward the development of an effective vaccine against porcine cysticercosis. A number of strategies have been proposed, including the use of parasite crude extracts (9, 17), recombinant proteins (2, 3, 15), synthetic peptides (4), phage display (8), and genetic immunization (10, 18). Genetic vaccines are particularly appealing for applications in developing countries as they can be inexpensive to produce and store (5). In the present study, we evaluated the use of genetic immunization with the amino-terminal fragment of T. solium paramyosin (VW2-1), which was previously shown to be protective (15), as an alternative strategy for vaccination in the murine model of Taenia crassiceps cysticercosis.A plasmid construct encoding a synthetic sequence for VW2-1 was designed for genetic immunization. The codon usage of the wild-type coding sequence for VW2-1 was adapted for mammalian cells (synVW2-1) by using procedures for gene synthesis (1). Briefly, a set of overlapping 60-mer oligonucleotides were assembled by PCR to construct synVW2-1, which was inserted into the pCMV plasmid vector (14). The construct was confirmed by DNA sequencing before large-scale purification with a QIAGEN Endofree Plasmid Giga kit (QIA-GEN). A comparison of the wild-type and synthetic sequences of VW2-1 showed substantial changes in first (11.2%), second (4.85%), and third (52.6%) positions of codons. An extensive comparison of the outcomes of the immune responses elicited in mice genetically immunized with wild-type VW2-1 and with synVW2-1 consistently showed higher antibody and cellular immune responses with the synthetic gene (data not shown). The synthetic coding sequence is available from us upon request.Vaccination assays were carried out by using 8-to 10-weekold female BALB/c mice that were bilaterally inoculated in the tibialis anterior muscle with pCMV-synVW2-1 or pCMV blank vector (100 g of DNA per mouse in 100 l of 0.9% saline). A third group contained naïve mice. After 2 and 4 weeks, mice were boosted with identical doses of plasmid DNA.In order to evaluate if the antibodies raised by genetic immunization were cross-reactive with paramyosins of T. solium and T. crassiceps, Western blot assays were carried out as described previously (16). Briefly, nitrocellulose membranes were blotted with recombinant full-length TPmy (recTPmy) and recombinant VW2-1 (recVW2-1) or with crude protein extracts from T. solium and T. crassiceps cysts (6). M...