Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine

Background

Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis.

Methodology/Principal Findings

In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. On the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms.

Conclusions/Significance

These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates.     

Outer membrane vesicles from group B Neisseria meningitidis delta gna33 mutant: proteomic and immunological comparison with detergent-derived outer membrane vesicles

We compared the proteome of detergent-derived group B Neisseria meningitidis (MenB) outer membrane vesicles (DOMVs) with the proteome of outer membrane vesicles (m-OMVs) spontaneously released into culture supernatant by MenB delta gna33, a mutant in which the gene coding for a lytic transglycosylase homologous to the E. coli MltA was deleted. In total, 138 proteins were identified in DOMVs by 1- and 2-DE coupled with MS; 64% of these proteins belonged to the inner membrane and cytoplasmic compartments. By contrast, most of the 60 proteins of m-OMVs were classified by PSORT as outer membrane proteins. When tested for their capacity to elicit bactericidal antibodies, m-OMVs elicited a broad protective activity against a large panel of MenB strains. Therefore, the identification of mutations capable of conferring an OMV-releasing phenotype in bacteria may represent an attractive approach to study bacterial membrane composition and organization, and to design new efficacious vaccine formulations.     

Energy budget of juvenile fat snook Centropomus parallelus fed live food

The fat snook Centropomus parallelus is a tropical estuarine species with importance for recreational and commercial fisheries and further aquaculture potential. Considering ingested energy (C) is channeled into growth (P), metabolic expenditure (R), excretion (U) and feces (F), a balanced energy budget was established for isolated and grouped juvenile C. parallelus (5.18 to 10.25 g wet mass) by experimental quantification of each of these parameters. Fish were fed live prawn (Macrobrachium sp.) at 25 degrees C and 20 per thousand for 19 days and daily energy budgets could be calculated. Energy content of food (live prawn), fish whole body and feces were 17.7, 14.5 and 6.1 KJ g(-1) dry mass (DW), respectively. Mass-specific rates of oxygen consumption and ammonia-N excretion were 0.271 and 0.0082 mg of O(2) or NH(3)-N g(-1) wet mass (WW) h(-1), respectively, resulting in O:N=23.4. Daily ingestion (C) was dependent on the amount of food offered and ranged between 4.9% to 7.4% of initial wet weight. Growth (P) was positively correlated with initial mass varying from 0.008 to 0.104 g day(-1). Feces release also correlated to fish mass and averaged 9.53 mg dry mass day(-1). The components of energy budget showed mean values of 2.39 (C), 0.24 (P), 1.96 (R), 0.11 (U) and 0.06 (F) KJ ind(-1) day(-1). As percentage of ingested energy, C. parallelus channeled 10% in growth (P), 82% in metabolism (R), 4.6% in excretion (U) and 2.5% in feces (F). Gross (K(1)) and net (K(2)) growth efficiencies were 9.2% and 9.9%, respectively. On the course of this period of juvenile development, K(1) and K(2) increased significantly. Partitioning of ingested energy in P, R, U and F was significantly different in individually and group maintained fish (P<0.05). Energy budget of C. parallelus fed a highly digestible diet (live prawn) revealed poor growth and growth efficiencies (K(1) and K(2)) possibly associated with an elevated metabolic demand and a high channeling of metabolized energy (P+R) into metabolism (R) in both isolated and grouped fish. Data can be applied to ecosystem modeling and may contribute to identify species potential to aquaculture.     

Identification of an I-Ad restricted peptide on the 65-kilodalton heat shock protein of Mycobacterium avium

The 65 kilodalton heat shock protein (Hsp65) from mycobacterial species elicits immune responses and in some cases protective immunity. Here we have used a DNA sublibrary approach to identify antigenic fragments of Mycobacterium avium Hsp65 and a synthetic peptide approach to delineate CD4+ T cell determinants. A panel of Hsp65 reactive CD4+ T cell clones was established from lymph node cells obtained from BALB/c mice immunized with recombinant Hsp65. The clones were tested for proliferative reactivity against the products of the DNA sublibrary of the hsp65 gene. A T cell epitope, restricted by the I-Ad molecule, was identified within the C-terminal region of Hsp65 and the minimal epitope (amino acid residues 489-503) delineated using overlapping peptides spanning the C-terminal fragment. Additionally, the CD4+ T cell clone recognizing this epitope also responded to native Hsp65 present in M. avium lysates by both proliferation and cytokine production, indicating that the epitope was present and processed similarly both in the native and the recombinant forms of Hsp65. This sequence identified in BALB/c mice (Hsp65 489-503) is identical in other mycobacteria, notably M. tuberculosis, M. bovis and M. leprae, suggesting the epitope may have wider application in murine models of other mycobacterial infections.     

Surnames in Bolivia: A study of the population of Bolivia through isonymy

In Bolivia, the Hispanic dual surname system is used. To describe the isonymic structure of Bolivia, the surname distribution of 12,139,448 persons registered in the 2006 census data was studied in 9 districts and 112 provinces of the nation, for a total of 23,244,064 surnames. The number of different surnames found was 174,922. Matrices of isonymic distances between the administrative units (districts and provinces) were constructed and tested for correlation with geographic distance. In the 112 provinces, isonymic distances were correlated with geographic distance (r = 0.545 ± 0.011 for Euclidean, 0.501 ± 0.012 for Nei's, and 0.556 ± 0.010 for Lasker's distance). The multiple regression of the surname effective number (α), equivalent to the allele effective number in a genetic system, was nonsignificant on latitude and longitude; however, it was highly significant and negative on altitude (r = ?0.72). Because the Andes extend from north to south in west‐central Bolivia, random inbreeding was lowest in the eastern districts, and highest in mountainous western Bolivia. Average α for the provinces was 122 ± 2; for the districts, it was 216 ± 29, and for the whole of Bolivia it was 213. The geographical distribution of α in the provinces is compatible with the settlement of subsequent groups of migrants moving from east and north toward the center and south of Bolivia. The relative frequency of indigenous surnames is correlated positively with altitude. This suggests that the country was populated by recent low‐density demic diffusion over a low‐density indigenous population. This may have been a common phenomenon in the immigration to tropical South America. Am J Phys Anthropol, 2011. © 2010 Wiley‐Liss, Inc.     

The adaptive potential of a plant pathogenic fungus, <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> AG-3, under heat and fungicide stress

The ability to improve fitness via adaptive evolution may be affected by environmental change. We tested this hypothesis in an in vitro experiment with the plant pathogen Rhizoctonia solani Anastomosis Group 3 (AG-3), assessing genetic and environmental variances under two temperatures (optimal and higher than optimal) and three fungicide concentrations (no fungicide, low and high concentration of a copper-based fungicide). We measured the mean daily growth rate, the coefficient of variation for genotypic (I _G) and environmental variance (I _E) in growth, and broad-sense heritability in growth. Both higher temperature and increased fungicide concentration caused a decline in growth, confirming their potential as stressors for the pathogen. All types of standardized variances in growth—I _G, phenotypic variance, and I _E as a trend—increased with elevated stress. However, heritability was not significantly higher under enhanced stress because the increase in I _G was counterbalanced by somewhat increased I _E. The results illustrate that predictions for adaptation under environmental stress may depend on the type of short-term evolvability measure. Because mycelial growth is linked to fitness, I _G reflects short-term evolvability better than heritability, and it indicates that the evolutionary potential of R. solani is positively affected by stress.     

Non-peptide NK1 receptor ligands based on the 4-phenylpyridine moiety

The quinoline nucleus of the previously described 4-phenylquinoline-3-carboxamides NK(1) receptor ligands 7 has been transformed into either substituted or azole-(i.e., triazole or tetrazole) fused pyridine moieties of compounds 9 and 10, respectively, in order to obtain NK(1) receptor ligands showing lower molecular weight or higher hydrophilicity. The program of molecular manipulations produced NK(1) receptor ligands showing affinity in the nanomolar range. In particular, 4-methyl-1-piperazinyl derivative 9j showed an IC(50) value of 4.8 nM and was proved to behave as a NK(1) antagonist blocking Sar(9)-SP-sulfone induced proliferation and migration of microvascular endothelial cells. Therefore, compound 9j has been labeled with [(11)C]CH(3)I (t(1/2)=20.4 min, β(+)=99.8%) starting from the corresponding des-methyl precursor 9i using with a radiochemical yield of about 10% (not decay corrected) and a specific radioactivity>1 Ci/μmol in order to be used as a radiotracer in next PET studies.     

Analysis of ovarian cancer cell secretome during epithelial to mesenchymal transition reveals a protein signature associated with advanced stages of ovarian tumors

Ovarian cancer (OvCA) is the most lethal neoplasia among gynecologic malignancies and faces high rates of new cases particularly in South America. In special, the High Grade Serous Ovarian Carcinoma (HGSC) presents very poor prognosis with deaths caused mainly by metastasis. Among several mechanisms involved in metastasis, the Epithelial to Mesenchymal Transition (EMT) molecular reprogramming represents a model for latest stages of cancer progression. EMT promotes important cellular changes in cellular adhesion and cell-cell communication, which particularly depends on the paracrine signaling from neighbor cells. Considering the importance of cellular communication during EMT and metastasis, here we analyzed the changes in the secretome of the ovarian cancer cell line Caov-3 induced to EMT by Epidermal Growth Factor (EGF). Using a combination of GEL-LC-MS/MS and stable isotopic metabolic labelling (SILAC), we identified up-regulated candidates during EMT as a starting point to identify relevant proteins for HGSC. Based on public databases, our candidate proteins were validated and prioritized for further analysis. Importantly, several of the protein candidates were associated with cellular vesicles, which are important to the cell-cell communication and metastasis. Furthermore, the association of candidate proteins with gene expression data uncovered a subset of proteins correlated with the mesenchymal subtype of ovarian cancer. Based on this relevant molecular signature for aggressive ovarian cancer, supported by protein and gene expression data, we developed a targeted proteomic method to evaluate individual OvCA clinical samples. The quantitative information obtained for 33 peptides, representative of 18 proteins, was able to segregate HGSC from other tumor types. Our study highlighted the richness of the secretome and EMT to reveal relevant proteins for HGSC, which could be used in further studies and larger patient cohorts as a potential stratification signature for ovarian cancer tumor that could guide clinical conduct for patient treatment.