Proteomics and Leishmaniasis: Potential Clinical Applications.

Leishmaniases are diseases caused by protozoan parasites of the genus Leishmania. They are endemic in 98 countries, affect around 12 million people worldwide and may present several distinct clinical forms. Unfortunately, there are only a few drugs available for treatment of leishmaniasis, which are toxic and not always effective. Different parasite species and different clinical forms require optimization of the treatment or more specific therapies, which are not available. The emergence of resistance is also a matter of concern. Besides, diagnosis can sometimes be complicated due to atypical manifestations and associations with other pathologies. In this review, proteomic data are presented and discussed in terms of their application in important issues in leishmaniasis such as parasite resistance to chemotherapy, diagnosis of active disease in patients and dogs, markers for different clinical forms, identification of virulence factors, and their potential use in vaccination. It is shown that proteomics has contributed to the discovery of potential biomarkers for prognosis, diagnosis, therapeutics, monitoring of disease progression, treatment follow-up and identification of vaccine candidates for specific diseases. However, the authors believe its capabilities have not yet been fully explored for routine clinical analysis for several reasons, which will be presented in this review.

CD100 Effects in Macrophages and Its Roles in Atherosclerosis.

CD100 or Sema4D is a protein from the semaphorin family with important roles in the vascular, nervous and immune systems. It may be found as a membrane bound dimer or as a soluble molecule originated by proteolytic cleavage. Produced by the majority of hematopoietic cells including B and T lymphocytes, natural killer and myeloid cells, as well as endothelial cells, CD100 exerts its actions by binding to different receptors depending on the cell type and on the organism. Cell-to-cell adhesion, angiogenesis, phagocytosis, T cell priming, and antibody production are examples of the many functions of this molecule. Of note, high CD100 serum levels has been found in inflammatory as well as in infectious diseases, but the roles of the protein in the pathogenesis of these diseases has still to be clarified. Macrophages are highly heterogeneous cells present in almost all tissues, which may change their functions in response to microenvironmental conditions. They are key players in the innate and adaptive immune responses and have decisive roles in sterile conditions but also in several diseases such as atherosclerosis, autoimmunity, tumorigenesis, and antitumor responses, among others. Although it is known that macrophages express CD100 and its receptors, few studies have focused on the role of this semaphorin in this cell type or in macrophage-associated diseases. The aim of this review is to critically revise the available data about CD100 and atherosclerosis, with special emphasis on its roles in macrophages and monocytes. We will also describe the few available data on treatments with anti-CD100 antibodies in different diseases. We hope that this review stimulates future studies on the effects of such an important molecule in a cell type with decisive roles in inflammatory diseases such as atherosclerosis.

Immune-related redox metabolism of embryonic cells of the tick Rhipicephalus microplus (BME26) in response to infection with Anaplasma marginale.

BACKGROUND: It is well known that reactive oxygen species (ROS) and reactive nitrogen species (RNS) are involved in the control of pathogens and microbiota in insects. However, the knowledge of the role of ROS and RNS in tick-pathogen and tick-microbiota interactions is limited. Here, we evaluated the immune-related redox metabolism of the embryonic cell line BME26 from the cattle tick Rhipicephalus microplus in response to Anaplasma marginale infection. METHODS: A high-throughput qPCR approach was used to determine the expression profile of 16 genes encoding proteins involved in either production or detoxification of ROS and RNS in response to different microbial challenges. In addition, the effect of RNAi-mediated gene silencing of catalase, glutathione peroxidase, thioredoxin and protein oxidation resistance 1 in the control of infection with A. marginale was evaluated. RESULTS: Infection with A. marginale resulted in downregulation of the genes encoding ROS-generating enzymes dual oxidase and endoplasmic reticulum oxidase. In contrast, the genes encoding the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, thioredoxin, thioredoxin reductase and peroxiredoxin were upregulated. The gene expression pattern in response to infection with Rickettsia rickettsii and exposure to heat-killed microorganisms, Micrococcus luteus, Enterobacter cloacae or S. cerevisiae was the opposite of that triggered by A. marginale challenge. The simultaneous silencing of three genes, catalase, glutathione peroxidase, and thioredoxin as well as the oxidation resistance 1 gene by RNAi apparently favoured the colonization of BME26 cells by A. marginale, suggesting that the antioxidant response might play a role in the control of infection. CONCLUSIONS: Taken together, our results suggest that a general response of tick cells upon microbial stimuli is to increase ROS/RNS production. In contrast, A. marginale infection triggers an opposite profile, suggesting that this pathogen might manipulate the tick redox metabolism to evade the deleterious effect of the oxidant-based innate immune response.

Exploring the immune signalling pathway-related genes of the cattle tick Rhipicephalus microplus: From molecular characterization to transcriptional profile upon microbial challenge.

In dipteran insects, invading pathogens are selectively recognized by four major pathways, namely Toll, IMD, JNK, and JAK/STAT, and trigger the activation of several immune effectors. Although substantial advances have been made in understanding the immunity of model insects such as Drosophila melanogaster, knowledge on the activation of immune responses in other arthropods such as ticks remains limited. Herein, we have deepened our understanding of the intracellular signalling pathways likely to be involved in tick immunity by combining a large-scale in silico approach with high-throughput gene expression analysis. Data from in silico analysis revealed that although both the Toll and JAK/STAT signalling pathways are evolutionarily conserved across arthropods, ticks lack central components of the D. melanogaster IMD pathway. Moreover, we show that tick immune signalling-associated genes are constitutively transcribed in BME26 cells (a cell lineage derived from embryos of the cattle tick Rhipicephalus microplus) and exhibit different transcriptional patterns in response to microbial challenge. Interestingly, Anaplasma marginale, a pathogen that is naturally transmitted by R. microplus, causes downregulation of immune-related genes, suggesting that this pathogen may manipulate the tick immune system, favouring its survival and vector colonization.

Phage-displayed peptides as capture antigens in an innovative assay for Taenia saginata-infected cattle.

Bovine cysticercosis is detected during the routine post mortem examination of carcasses by visual inspection (knife and eye method). However, the sensitivity of this procedure is several times lower than immunoassays, even when it is performed by qualified professionals. In the present study, a new generation capture antigens were screened from a phage display peptide library using antibodies from Taenia saginata-infected animals. Eight phage clones were selected, and one, Tsag 3 (VHTSIRPRCQPRAITPR), produced similar results to the T. saginata metacestode crude antigen (TsCa) when used as a capture antigen in an ELISA. The phage-displayed peptides competed with TsCa for binding sites, reducing the reactivity by approximately 30 %. Alanine scanning indicated that proline, arginine, and serine are important residues for antibody binding. Tsag 1 (HFYQITWLPNTFPAR), the most frequent affinity-selected clone, and Tsag 6 (YRWPSTPSASRQATL) shared similarity with highly conserved proteins from the Taeniidae family with known immunogenicity. Due to their epitopic or mimotopic properties, these affinity-selected phages could contribute to the rational design of an ante mortem immunodiagnosis method for bovine cysticercosis, as well as an epitope-based vaccine to interrupt the taeniosis/cysticercosis complex.

Evaluation of the protective potential of a Taenia solium cysticercus mimotope on murine cysticercosis.

An NC-1 mimotope from Taenia solium cysticerci can help identify patients with neurocysticercosis through immunoassay. After chemical synthesis, an NC-1 peptide was coupled to bovine serum albumin (NC-1/BSA) for used as an immunogen in murine Taenia crassiceps cysticercosis, which is an experimental model of cysticercosis caused by T. solium. NC-1/BSA immunisation decreased parasitaemia by inducing 74% protection compared to the 77% protection obtained with T. crassiceps crude antigen. The influence of immunisation was also observed on the size and stage of development of the parasite. Antibodies from NC-1/BSA-immunised mice recognised proteins from the tegument and from the buddings, and intense immunostaining was observed in the final stage of the metacestode. The capacity of NC-1/BSA to induce protective antibodies which are reactive to proteins from the tegument of the metacestode suggests that this mimotope is a potential candidate for a vaccine against human and animal cysticercosis.