Expression, Polyubiquitination, and Therapeutic Potential of Recombinant E6E7 from HPV16 Antigens Fused to Ubiquitin.

Ubiquitin-proteasome system plays an essential role in the immune response due to its involvement in the antigen generation and presentation to CD8+ T cells. Hereby, ubiquitin fused to antigens has been explored as an immunotherapeutic strategy that requires the activation of cytotoxic T lymphocytes. Here we propose to apply this ubiquitin fusion approach to a recombinant vaccine against human papillomavirus 16-infected cells. E6E7 multi-epitope antigen was fused genetically at its N- or C-terminal end to ubiquitin and expressed in Escherichia coli as inclusion bodies. The antigens were solubilized using urea and purified by nickel affinity chromatography in denatured condition. Fusion of ubiquitin to E6E7 resulted in marked polyubiquitination in vitro mainly when fused to the E6E7 N-terminal. When tested in a therapeutic scenario, the fusion of ubiquitin to E6E7 reinforced the anti-tumor protection and increased the E6/E7-specific cellular immune responses. Present results encourage the investigation of the adjuvant potential of the ubiquitin fusion to recombinant vaccines requiring CD8+ T cells.

Proteomic identification of gender molecular markers in Bothrops jararaca venom.

Variation in the snake venom proteome is a well-documented phenomenon; however, sex-based variation in the venom proteome/peptidome is poorly understood. Bothrops jararaca shows significant sexual size dimorphism and here we report a comparative proteomic/peptidomic analysis of venoms from male and female specimens and correlate it with the evaluation of important venom features. We demonstrate that adult male and female venoms have distinct profiles of proteolytic activity upon fibrinogen and gelatin. These differences were clearly reflected in their different profiles of SDS-PAGE, two-dimensional electrophoresis and glycosylated proteins. Identification of differential protein bands and spots between male or female venoms revealed gender-specific molecular markers. However, the proteome comparison by in-solution trypsin digestion and label-free quantification analysis showed that the overall profiles of male and female venoms are similar at the polypeptide chain level but show striking variation regarding their attached carbohydrate moieties. The analysis of the peptidomes of male and female venoms revealed different contents of peptides, while the bradykinin potentiating peptides (BPPs) showed rather similar profiles. Furthermore we confirmed the ubiquitous presence of four BPPs that lack the C-terminal Q-I-P-P sequence only in the female venom as gender molecular markers. As a result of these studies we demonstrate that the sexual size dimorphism is associated with differences in the venom proteome/peptidome in B. jararaca species. Moreover, gender-based variations contributed by different glycosylation levels in toxins impact venom complexity. BIOLOGICAL SIGNIFICANCE: Bothrops jararaca is primarily a nocturnal and generalist snake species, however, it exhibits a notable ontogenetic shift in diet and in venom proteome upon neonate to adult transition. As is common in the Bothrops genus, B. jararaca shows significant sexual dimorphism in snout-vent length and weight, with females being larger than males. This sexual size dimorphism suggests the tendency for female specimens to feed on larger prey, and for male specimens to go on a diet similar to that of juveniles. Variation in the snake venom proteome is a ubiquitous phenomenon occurring at all taxonomic levels. At the intraspecific variation level, the individual contribution to the venom proteome is important but effects contributed by age and feeding habits may also affect the proteome phenotype. Whether sex-based factors play a role in venom variation of a species that shows sexual size dimorphism is poorly known. The use of proteomic strategies supported by transcriptomic data allows a more comprehensive assessment of venom proteomes uncovering components that are gender-specific.

Controlled inflammatory responses in the lungs are associated with protection elicited by a pneumococcal surface protein A-based vaccine against a lethal respiratory challenge with Streptococcus pneumoniae in mice.

Streptococcus pneumoniae is a pathogen of great importance worldwide. We have previously described the efficacy of a nasal vaccine composed of the pneumococcal surface protein A and the whole-cell pertussis vaccine as an adjuvant against a pneumococcal invasive challenge in mice. Spread of bacteria to the bloodstream was probably prevented by the high levels of systemic antibodies induced by the vaccine, but bacteria were only cleared from the lungs 3 weeks later, indicating that local immune responses may contribute to survival. Here we show that a strict control of inflammatory responses in lungs of vaccinated mice occurs even in the presence of high numbers of pneumococci. This response was characterized by a sharp peak of neutrophils and lymphocytes with a simultaneous decrease in macrophages in the respiratory mucosa at 12 h postchallenge. Secretion of interleukin-6 (IL-6) and gamma interferon (IFN-γ) was reduced at 24 h postchallenge, and the induction of tumor necrosis factor alpha (TNF-α) secretion, observed in the first hours postchallenge, was completely abolished at 24 h. Before challenge and at 12 h postchallenge, vaccinated mice displayed higher numbers of CD4(+) T, CD8(+) T, and B lymphocytes in the lungs. However, protection still occurs in the absence of each of these cells during the challenge, indicating that other effectors may be related to the prevention of lung injuries in this model. High levels of mucosal anti-PspA antibodies were maintained in vaccinated mice during the challenge, suggesting an important role in protection.

The action of topical basic fibroblast growth factor in facial nerve regeneration.

OBJECTIVE: To analyze the influence of the topical use of basic fibroblast growth factor (bFGF) in the regeneration of the facial nerve in rats. STUDY DESIGN: Experimental study. MATERIALS AND METHODS: Twenty-eight Wistar adult male rats underwent complete section of the facial nerve trunk, followed by end-to-end anastomosis with epineural sutures. An osmotic minipump equipped with a delivery catheter was implanted subcutaneously near the neural anastomosis. During the subsequent 14 days, 14 animals received a solution containing 25 microg/ml of bFGF, 250 UI/ml of sodium heparin, and 1,000 microg/ml of human albumin diluted in Ringer lactate, and 14 animals received a control solution of the same components without bFGF. To evaluate facial nerve regeneration, the number of myelinated fibers evident on histologic sections was counted on the 14th (7 experimental and 8 control animals) and the 28th days (7 experimental and 6 control animals) after surgery, and the facial movements of vibrissae and the blink reflex were evaluated on alternate days until the 28th day. RESULTS: On histologic evaluation, the number of myelinated fibers was similar between groups on the 14th day and greater in the group that received bFGF on the 28th day. Behavioral evaluation showed that the animals of the bFGF group presented better functional results between the 6th and 16th days for the blink test and the 14th to the 16th days for vibrissae movements. CONCLUSION: This study showed that the regeneration of the facial nerve occurred earlier and resulted in significantly more myelinated nerve fibers in the animals that received topical bFGF.

Comparison of the pulmonary response against lethal and non-lethal intranasal challenges with two different pneumococcal strains.

The differences between the immune response elicited during a self-limiting and a life-threatening lung infection with Streptococcus pneumoniae was analyzed in a mouse model of intranasal challenge using two different pneumococcal strains. M10, a serotype 11A strain, induced an early response within the first 12h after the challenge, which was characterized by the early local secretion of TNF-alpha and IL-6, followed by a sharp and rapid neutrophil influx. Bacterial loads in the lungs already started to fall at 12h after the challenge and no pneumococci could be recovered after 36h, at the time point when the animals started to show improvement in disease symptoms. ATCC6303, a serotype 3 strain, on the other hand, showed only a late increase in local TNF-alpha and IL-6 levels, when bacterial growth already seems to be out of control. Although cell influx was also observed, neutrophil rise was not as marked as with M10 (type 11A). Pneumococcal loads increased constantly and bacteria started to be recovered from the blood at 30h after the challenge. After this time point, animals showed worsening of symptoms and became lethargic. The resolution of the acute infection could be thus correlated with the early induction of proinflammatory cytokines, which could be due to the presence of a thinner polysaccharide capsule in M10 (type 11A), rendering bacterial components capable of activating the innate immune response more accessible.

Crystallization and preliminary X-ray analysis of LipL32 from Leptospira interrogans serovar Copenhageni.

LipL32 is a major surface protein that is expressed during infection by pathogenic Leptospira. Here, the crystallization of recombinant LipL32(21-272), which corresponds to the mature LipL32 protein minus its N-terminal lipid-anchored cysteine residue, is described. Selenomethionine-labelled LipL32(21-272) crystals diffracted to 2.25 A resolution at a synchrotron source. The space group was P3(1)21 or P3(2)21 and the unit-cell parameters were a = b = 126.7, c = 96.0 A.

Bothrops insularis venomics: a proteomic analysis supported by transcriptomic-generated sequence data.

A joint transcriptomic and proteomic approach employing two-dimensional electrophoresis, liquid chromatography and mass spectrometry was carried out to identify peptides and proteins expressed by the venom gland of the snake Bothrops insularis, an endemic species of Queimada Grande Island, Brazil. Four protein families were mainly represented in processed spots, namely metalloproteinase, serine proteinase, phospholipase A(2) and lectin. Other represented families were growth factors, the developmental protein G10, a disintegrin and putative novel bradykinin-potentiating peptides. The enzymes were present in several isoforms. Most of the experimental data agreed with predicted values for isoelectric point and M(r) of proteins found in the transcriptome of the venom gland. The results also support the existence of posttranslational modifications and of proteolytic processing of precursor molecules which could lead to diverse multifunctional proteins. This study provides a preliminary reference map for proteins and peptides present in Bothrops insularis whole venom establishing the basis for comparative studies of other venom proteomes which could help the search for new drugs and the improvement of venom therapeutics. Altogether, our data point to the influence of transcriptional and post-translational events on the final venom composition and stress the need for a multivariate approach to snake venomics studies.

Immunization of mice with Lactobacillus casei expressing intimin fragments produces antibodies able to inhibit the adhesion of enteropathogenic Escherichia coli to cultivated epithelial cells.

Enteropathogenic Escherichia coli (EPEC) are frequently isolated as a cause of infantile diarrhea in developing countries. Its pathogenicity is distinguished by histopathological alterations at the site of infection, known as attaching and effacing (A/E) lesions, in which bacterial virulence factors and host proteins participate. Intimin, a bacterial adhesin expressed by all EPEC described to date, is responsible for the intimate adherence of the bacteria to host cells and is essential for the formation of A/E lesions. Mucosal vaccination may represent an efficacious intervention to prevent EPEC infection and lower morbidity and mortality rates. Strategies for mucosal vaccinations that use lactic acid bacteria for the delivery of heterologous antigens rely on their safety profile and ability to stimulate the immune system. In the present work, we have constructed Lactobacillus casei strains expressing different fragments of intimin beta, a subtype that is frequently expressed by EPEC strains. Mucosal immunization of mice with L. casei expressing intimin fragments induced specific systemic and mucosal antibodies. These antibodies were able to recognize native intimin on the surface of EPEC and to inhibit in vitro EPEC binding to epithelial cells.

Transcriptome analysis of Loxosceles laeta (Araneae, Sicariidae) spider venomous gland using expressed sequence tags.

BACKGROUND: The bite of spiders belonging to the genus Loxosceles can induce a variety of clinical symptoms, including dermonecrosis, thrombosis, vascular leakage, haemolysis, and persistent inflammation. In order to examine the transcripts expressed in venom gland of Loxosceles laeta spider and to unveil the potential of its products on cellular structure and functional aspects, we generated 3,008 expressed sequence tags (ESTs) from a cDNA library. RESULTS: All ESTs were clustered into 1,357 clusters, of which 16.4% of the total ESTs belong to recognized toxin-coding sequences, being the Sphingomyelinases D the most abundant transcript; 14.5% include "possible toxins", whose transcripts correspond to metalloproteinases, serinoproteinases, hyaluronidases, lipases, C-lectins, cystein peptidases and inhibitors. Thirty three percent of the ESTs are similar to cellular transcripts, being the major part represented by molecules involved in gene and protein expression, reflecting the specialization of this tissue for protein synthesis. In addition, a considerable number of sequences, 25%, has no significant similarity to any known sequence. CONCLUSION: This study provides a first global view of the gene expression scenario of the venom gland of L. laeta described so far, indicating the molecular bases of its venom composition.

Identification and cloning of snake venom vascular endothelial growth factor (svVEGF) from Bothrops erythromelas pitviper.

Vascular endothelial growth factors (VEGFs) are among the most important angiogenic proteins found on vertebrates. In the last years, some reports of the occurrence of such proteins in snake venoms are rising the importance of this family of proteins as toxins, since they appear to be involved in many features of Viperidae envenoming, such as hypotension and venom spread through increase in vascular permeability. Here we describe the occurrence of snake venom VEGF in Bothrops erythromelas, a clinical important snake from Northeast of Brazil, through immunodetection and cloning of its cDNA and briefly provide an overview comparison of all recent described svVEGF sequences.

Overexpression of a synthetic gene encoding human alpha interferon in Escherichia coli.

Interferons (IFNs) represent an important defense mechanism in vertebrates. In this work, we describe gene synthesis and assembly using the polymerase chain reaction as a method for single-step synthesis of DNA sequences. The oligonucleotides designed were based on Escherichia coli codon usage and two genes of IFN were synthesized: one containing a DNA sequence already known and the other, a mutated form in which two cysteine amino acid residues were replaced by serines in an attempt to improve the stability of the protein. DNA sequences were cloned into pAE, an E. coli vector that allows heterologous protein expression with or without a histidine tag. Recombinant human interferons (rhIFNs) were identified by Western blotting and ELISA using anti-human interferon polyclonal antibodies. Purification of the recombinant His-tagged proteins was achieved in a single step by Ni(2+)-charged column chromatography while proteins without His-tag were purified by extensively washing the inclusion bodies, the final yields being approximately 210 and 75mg/L, respectively. The rhIFNs expressed within this system were biologically active ( approximately 1,1x10(8)IU/mg) based on antiviral assay. The combined methodologies described here proved to be cost-effective and could be extended to other genes/proteins of interest.

A prothrombin activator from Bothrops erythromelas (jararaca-da-seca) snake venom: characterization and molecular cloning.

A novel prothrombin activator enzyme, which we have named 'berythractivase', was isolated from Bothrops erythromelas (jararaca-da-seca) snake venom. Berythractivase was purified by a single cation-exchange-chromatography step on a Resource S (Amersham Biosciences) column. The overall purification (31-fold) indicates that berythractivase comprises about 5% of the crude venom. It is a single-chain protein with a molecular mass of 78 kDa. SDS/PAGE of prothrombin after activation by berythractivase showed fragment patterns similar to those generated by group A prothrombin activators, which convert prothrombin into meizothrombin, independent of the prothrombinase complex. Chelating agents, such as EDTA and o -phenanthroline, rapidly inhibited the enzymic activity of berythractivase, like a typical metalloproteinase. Human fibrinogen A alpha-chain was slowly digested only after longer incubation with berythractivase, and no effect on the beta- or gamma-chains was observed. Berythractivase was also capable of triggering endothelial proinflammatory and procoagulant cell responses. von Willebrand factor was released, and the surface expression of both intracellular adhesion molecule-1 and E-selectin was up-regulated by berythractivase in cultured human umbilical-vein endothelial cells. The complete berythractivase cDNA was cloned from a B. erythromelas venom-gland cDNA library. The cDNA sequence possesses 2330 bp and encodes a preproprotein with significant sequence similarity to many other mature metalloproteinases reported from snake venoms. Berythractivase contains metalloproteinase, desintegrin-like and cysteine-rich domains. However, berythractivase did not elicit any haemorrhagic response. These results show that, although the primary structure of berythractivase is related to that of snake-venom haemorrhagic metalloproteinases and functionally similar to group A prothrombin activators, it is a prothrombin activator devoid of haemorrhagic activity. This is a feature not observed for most of the snake venom metalloproteinases, including the group A prothrombin activators.