Clinical, epidemiological and molecular features of the HIV-1 subtype C and recombinant forms that are circulating in the city of Sao Paulo, Brazil

Background: The city of Sao Paulo has the highest AIDS case rate, with nearly 60% in Brazil. Despite, several studies involving molecular epidemiology, lack of data regarding a large cohort study has not been published from this city. Objectives: This study aimed to describe the HIV-1 subtypes, recombinant forms and drug resistance mutations, according to subtype, with emphasis on subtype C and BC recombinants in the city of Sao Paulo, Brazil. Study design: RNA was extracted from the plasma samples of 302 HIV-1-seropositive subjects, of which 211 were drug-naive and 82 were exposed to ART. HIV-1 partial pol region sequences were used in phylogenetic analyses for subtyping and identification of drug resistance mutations. The envelope gene of subtype C and BC samples was also sequenced. Results: From partial pol gene analyses, 239 samples (79.1%) were assigned as subtype B, 23 (7.6%) were F1, 16 (5.3%) were subtype C and 24 (8%) were mosaics (3 CRF28/CRF29-like). The subtype C and BC recombinants were mainly identified in drug-naive patients (72.7%) and the heterosexual risk exposure category (86.3%), whereas for subtype B, these values were 69.9% and 57.3%, respectively (p = 0.97 and p = 0.015, respectively). An increasing trend of subtype C and BC recombinants was observed (p < 0.01). Conclusion: The HIV-1 subtype C and CRFs seem to have emerged over the last few years in the city of Sao Paulo, principally among the heterosexual population. These findings may have an impact on preventive measures and vaccine development in Brazil.

Protective immunity to DENV2 after immunization with a recombinant NS1 protein using a genetically detoxified heat-labile toxin as an adjuvant

The dengue virus non-structural 1 (NS1) protein contributes to evasion of host immune defenses and represents a target for immune responses. Evidences generated in experimental models, as well as the immune responses elicited by infected individuals, showed that induction of anti-NS1 immunity correlates with protective immunity but may also result in the generation of cross-reactive antibodies that recognize platelets and proteins involved in the coagulation cascade. In the present work, we evaluated the immune responses, protection to type 2 dengue virus (DENV2) challenges and safety parameters in BALB/c mice vaccinated with a recombinant NS1 protein in combination with three different adjuvants: aluminum hydroxide (alum), Freund's adjuvant (FA) or a genetically detoxified derivative of the heat-labile toxin (LTG33D), originally produced by some enterotoxigenic Escherichia coil (ETEC) strains. Mice were subcutaneously (s.c.) immunized with different vaccine formulations and the induced NS1-specific responses, including serum antibodies and T cell responses, were measured. Mice were also subjected to lethal challenges with the DENV2 NGC strain. The results showed that maximal protective immunity (50%) was achieved in mice vaccinated with NS1 in combination with LIG33D. Analyses of the NS1-specific immune responses showed that the anti-virus protection correlated mainly with the serum anti-NS1 antibody responses including higher avidity to the target antigen. Mice immunized with LTG33D elicited a prevailing IgG2a subclass response and generated antibodies with stronger affinity to the antigen than those generated in mice immunized with the other vaccine formulations. The vaccine formulations were also evaluated regarding induction of deleterious side effects and, in contrast to mice immunized with the FA-adjuvanted vaccine, no significant hepatic damage or enhanced C-reactive protein levels were detected in mice immunized with NS1 and LTG33D. Similarly, no detectable alterations in bleeding time and hematological parameters were detected in mice vaccinated with NS1 and LTG33D. Altogether, these results indicate that the combination of a purified recombinant NS1 and a nontoxic LT derivative is a promising alternative for the generation of safe and effective protein-based anti-dengue vaccine. (C) 2011 Elsevier Ltd. All rights reserved.

SK-HEP cells and lentiviral vector for production of human recombinant factor VIII

Hemophilia A is caused by a deficiency in coagulation factor VIII. Recombinant factor VIII can be used as an alternative although it is unavailable for most patients. Here, we describe the production of a human recombinant B-domain-deleted FVIII (rBDDFVIII) by the human cell line SK-HEP-1, modified by a lentiviral vector rBDDFVIII was produced by recombinant SK-HEP cells (rSK-HEP) at 1.5-2.1 IU/10(6) in 24 h. The recombinant factor had increased in vitro stability when compared to commercial pdFVIII. The functionality of rBDDFVIII was shown by its biological activity and by tail-clip challenge in hemophilia A mice. The rSK-HEP cells grew in a scalable system and produced active rBDDFVIII, indicating that this platform production can be optimized to meet the commercial production scale needs.

Expression of recombinant human mutant granulocyte colony stimulating factor (Nartograstim) in Escherichia coli

The human granulocyte colony stimulating factor (hG-CSF) plays an important role in hematopoietic cell proliferation/differentiation and has been widely used as a therapeutic agent for treating neutropenias. Nartograstim is a commercial G-CSF that presents amino acid changes in specific positions when compared to the wildtype form, which potentially increase its activity and stability. The aim of this work was to develop an expression system in Escherichia coli that leads to the production of large amounts of a recombinant hG-CSF (rhG-CSF) biosimilar to Nartograstim. The nucleotide sequence of hg-csf was codon-optimized for expression in E. coli. As a result, high yields of the recombinant protein were obtained with adequate purity, structural integrity and biological activity. This protein has also been successfully used for the production of specific polyclonal antibodies in mice, which could be used in the control of the expression and purification in an industrial production process of this recombinant protein. These results will allow the planning of large-scale production of this mutant version of hG-CSF (Nartograstim), as a potential new biosimilar in the market.

Leishmania (Viannia) shawi purified antigens confer protection against murine cutaneous leishmaniasis

Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis. Soluble antigen from L. (V.) shawi promastigotes was submitted to reverse phase HPLC to purify F1, F2, F3, F4 and F5 antigens. BALB/c mice were immunized once a week for two consecutive weeks by subcutaneous routes in the rump, using 25 mu g protein. After 1 week, groups were challenged in the footpad with L. (V.) shawi promastigotes. After 8 weeks, those same mice were sacrificed and parasite burden as well as the cellular and humoral immune responses were evaluated. F1 and F5-immunized mice restrained lesion progression and parasite load in the skin. However, only the F1 group was able to control the parasitism in lymph nodes, which was associated with low IL-4 and high IFN-gamma production; IgG2a isotype was increased in this group. Immunizations with F2, F3 and F4 antigens did not protect mice. The capability of antigens to restrain IL-4 levels and increase IFN-gamma was associated with protection, such as in immunization using F1 antigen.

Development of a recombinant fusion protein based on the dynein light chain LC8 for non-viral gene delivery

The low efficiency of gene transfer is a recurrent problem in DNA vaccine development and gene therapy studies using non-viral vectors such as plasmid DNA (pDNA). This is mainly due to the fact that during their traffic to the target cell's nuclei, plasmid vectors must overcome a series of physical, enzymatic and diffusional barriers. The main objective of this work is the development of recombinant proteins specifically designed for pDNA delivery, which take advantage of molecular motors like dynein, for the transport of cargos from the periphery to the centrosome of mammalian cells. A DNA binding sequence was fused to the N-terminus of the recombinant human dynein light chain LC8. Expression studies indicated that the fusion protein was correctly expressed in soluble form using E. coli BL21(DE3) strain. As expected, gel permeation assays found the purified protein mainly present as dimers, the functional oligomeric state of LC8. Gel retardation assays and atomic force microscopy proved the ability of the fusion protein to interact and condense pDNA. Zeta potential measurements indicated that LC8 with DNA binding domain (LD4) has an enhanced capacity to interact and condense pDNA, generating positively charged complexes. Transfection of cultured HeLa cells confirmed the ability of the LD4 to facilitate pDNA uptake and indicate the involvement of the retrograde transport in the intracellular trafficking of pDNA: LD4 complexes. Finally, cytotoxicity studies demonstrated a very low toxicity of the fusion protein vector, indicating the potential for in vivo applications. The study presented here is part of an effort to develop new modular shuttle proteins able to take advantage of strategies used by viruses to infect mammalian cells, aiming to provide new tools for gene therapy and DNA vaccination studies. (C) 2012 Elsevier B.V. All rights reserved.

Conformational stability of recombinant manganese superoxide dismutase from the filamentous fungus Trichoderma reesei

Superoxide dismutases (SODS; EC 1.15.1.1) are part of the antioxidant system of aerobic organisms and are used as a defense against oxidative injury caused by reactive oxygen species (ROS). The cloning and sequencing of the 788-bp genomic DNA from Trichoderma reesei strain QM9414 (anamorph of Hypocrea jecorina) revealed an open reading frame encoding a protein of 212 amino acid residues, with 65-90% similarity to manganese superoxide dismutase from other filamentous fungi. The TrMnSOD was purified and shown to be stable from 20 to 90 degrees C for 1 h at pH from 8 to 11.5, while maintaining its biological activity. (C) 2011 Elsevier B.V. All rights reserved.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 mu g of rhBMP-2, (3) laser and 7 mu g of rhBMP-2, (4) 7 mu g of rhBMP-2/monoolein gel, (5) laser and 7 mu g rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

Recombinant DNA immunotherapy ameliorate established airway allergy in a IL-10 dependent pathway

Background Previous studies have established that mycobacterial infections ameliorate allergic inflammation. However, a non-infectious approach that controls allergic responses might represent a safer and more promising strategy. The 60-65 kDa heat shock protein (Hsp) family is endowed with anti-inflammatory properties, but it is still unclear whether and how single mycobacterial Hsp control allergic disorders. Objective Therefore, in this study we determined whether the administration of Mycobacterial leprae Hsp65 expressed by recombinant a DNA plasmid could attenuate a previously established allergic response. Methods We used an experimental model of airway allergic inflammation to test the effects of immunotherapy with DNA encoding Hsp65. Allergic mice, previously sensitized and challenged with ovalbumin, were treated with tree intramuscular doses of recombinant DNA encoding Hsp65. After treatment, mice received a second allergen challenge and the allergic response was measured. Results We found that immunotherapy attenuated eosinophilia, pulmonary inflammation, Th2 cytokine and mucus production. Moreover, we showed that the inhibition of allergic response is dependent on IL-10 production. Both Hsp65 and allergen-specific IL-10-producing cells contributed to this effect. Cells transferred from DNA-immunized mice to allergic mice migrated to allergic sites and down-modulated the Th2 response. Conclusions and Clinical Relevance Our findings clearly show that immunotherapy with DNA encoding Hsp65 can attenuate an established Th2 allergic inflammation through an IL-10-dependent mechanism; moreover, the migration of allergen-and Hsp65-specific cells to the allergic sites exerts a fundamental role. This work represents a novel contribution to the understanding of immune regulation by Hsp65 in allergic diseases.

Phylogenetic analysis of complete genome sequences of hepatitis B virus from an Afro-Colombian community: presence of HBV F3/A1 recombinant strain

Background: Hepatitis B virus (HBV) infection is one of the most prevalent viral infections in humans and represents a serious public health problem. In Colombia, our group reported recently the presence of subgenotypes F3, A2 and genotype G in Bogota. The aim of this study was to characterize the HBV genotypes circulating in Quibdo, the largest Afro-descendant community in Colombia. Sixty HBsAg-positive samples were studied. A fragment of 1306 bp (S/POL) was amplified by nested PCR. Positive samples to S/POL fragment were submitted to PCR amplification of the HBV complete genome. Findings: The distribution of HBV genotypes was: A1 (52.17%), E (39.13%), D3 (4.3%) and F3/A1 (4.3%). An HBV recombinant strain subgenotype F3/A1 was found for the first time. Conclusions: This study is the first analysis of complete HBV genome sequences from Afro-Colombian population. It was found an important presence of HBV/A1 and HBV/E genotypes. A new recombinant strain of HBV genotype F3/A1 was reported in this population. This fact may be correlated with the introduction of these genotypes in the times of slavery.

Recombinant expression, localization and in vitro inhibition of midgut cysteine peptidase (Sl-CathL) from sugarcane weevil, Sphenophorus levis

A cDNA coding for a digestive cathepsin L, denominated Sl-CathL, was isolated from a cDNA library of Sphenophorus levis larvae, representing the most abundant EST (10.49%) responsible for proteolysis in the midgut. The open reading frame of 972 bp encodes a preproenzyme similar to midgut cathepsin L-like enzymes in other coleopterans. Recombinant Sl-CathL was expressed in Pichia pastoris, with molecular mass of about 42 kDa. The recombinant protein was catalytically activated at low pH and the mature enzyme of 39 kDa displayed thermal instability and maximal activity at 37 degrees C and pH 6.0. Immunocytochemical analysis revealed Sl-CathL production in the midgut epithelium and secretion from vesicles containing the enzyme into the gut lumen, confirming an important role for this enzyme in the digestion of the insect larvae. The expression profile identified by RT-PCR through the biological cycle indicates that Sl-CathL is mainly produced in larval stages, with peak expression in 30-day-old larvae. At this stage, the enzyme is 1250-fold more expressed than in the pupal fase, in which the lowest expression level is detected. This enzyme is also produced in the adult stage, albeit in lesser abundance, assuming the presence of a different array of enzymes in the digestive system of adults. Tissue-specific analysis revealed that Sl-CathL mRNA synthesis occurs fundamentally in the larval midgut, thereby confirming its function as a digestive enzyme, as detected in immunolocalization assays. The catalytic efficiency of the purified recombinant enzyme was calculated using different substrates (Z-Leu-Arg-AMC, Z-Arg-Arg-AMC and Z-Phe-Arg-AMC) and rSl-CathL exhibited hydrolysis preference for Z-Leu-Arg-AMC (k(cat)/K-m = 37.53 mM S-1), which is similar to other insect cathepsin L-like enzymes. rSl-CathL activity inhibition assays were performed using four recombinant sugarcane cystatins. rSl-CathL was strongly inhibited by recombinant cystatin CaneCPI-4 (K-i = 0.196 nM), indicating that this protease is a potential target for pest control. (C) 2011 Elsevier Ltd. All rights reserved.

Influence of low-level laser associated with osteogenic proteins recombinant human BMP-2 and Hevea brasiliensis on bone repair in Wistar rats

This study analyzed the newly formed bone tissue after application of recombinant human BMP-2 (rhBMP-2) and P-1 (extracted from Hevea brasiliensis) proteins, 2 weeks after the creation of a critical bone defect in male Wistar rats treated or not with a low-intensity laser (GaAlAs 780 nm, 60 mW of power, and energy density dose of 30 J/cm2). The animals were divided into two major groups: (1) bone defect plus low-intensity laser treatment and (2) bone defect without laser irradiation. The following subgroups were also analyzed: (a) 5 mu g of pure rhBMP-2; (b) 5 mu g of pure P-1 fraction; (c) 5 mu g of rhBMP-2/monoolein gel; (d) 5 mu g of P-1 fraction/monoolein gel; (e) pure monoolein gel. Comparisons of the groups receiving laser treatment with those that did not receive laser irradiation show differences in the areas of new bone tissue. The group treated with 5 mu g of rhBMP-2 and laser irradiation was not significantly different (P >0.05) than the nonirradiated group that received the same treatment. The irradiated, rhBMP-2/monoolein gel treatment group showed a lower area of bone formation than the nonirradiated, rhBMP-2/gel monoolein treatment group (P < 0.001). The area of new bone tissue in the other nonirradiated and irradiated groups was not significantly different (P > 0.05). Furthermore, the group that received the 5 mu g of rhBMP-2 application showed the greatest bone formation. We conclude that the laser treatment did not interfere with the area of new bone tissue growth and that the greatest stimulus for bone formation involved application of the rhBMP-2 protein. Microsc. Res. Tech. 2011. (c) 2011 Wiley Periodicals, Inc.

Functional characterization and oligomerization of a recombinant xyloglucan-specific endo-beta-1,4-glucanase (GH12) from Aspergillus niveus

Xyloglucan is a major structural polysaccharide of the primary (growing) cell wall of higher plants. It consists of a cellulosic backbone (beta-1,4-linked glucosyl residues) that is frequently substituted with side chains. This report describes Aspergillus nidulans strain A773 recombinant secretion of a dimeric xyloglucan-specific endo-beta-1,4-glucanohydrolase (XegA) cloned from Aspergillus niveus. The ORF of the A. niveus xegA gene is comprised of 714 nucleotides, and encodes a 238 amino acid protein with a calculated molecular weight of 23.5 kDa and isoelectric point of 4.38. The optimal pH and temperature were 6.0 and 60 degrees C, respectively. XegA generated a xyloglucan-oligosaccharides (XGOs) pattern similar to that observed for cellulases from family GH12, i.e., demonstrating that its mode of action includes hydrolysis of the glycosidic linkages between glucosyl residues that are not branched with xylose. In contrast to commercial lichenase, mixed linkage beta-glucan (lichenan) was not digested by XegA, indicating that the enzyme did not cleave glucan beta-1,3 or beta-1,6 bonds. The far-UV CD spectrum of the purified enzyme indicated a protein rich in beta-sheet structures as expected for GH12 xyloglucanases. Thermal unfolding studies displayed two transitions with mid-point temperatures of 51.3 degrees C and 81.3 degrees C respectively, and dynamic light scattering studies indicated that the first transition involves a change in oligomeric state from a dimeric to a monomeric form. Since the enzyme is a predominantly a monomer at 60 degrees C. the enzymatic assays demonstrated that XegA is more active in its monomeric state. (c) 2012 Elsevier B.V. All rights reserved.

Generation of a Chinese Hamster Ovary Cell Line Producing Recombinant Human Glucocerebrosidase

Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR) results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher's patients, which reaches the order of $ 84million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr(-)) cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (similar to 64 and 59 kDa) and secreted (63-69 kDa) form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditionalmethods of screening high-producing recombinant cellsmay represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources.

Selective Permeation and Organic Extraction of Recombinant Green Fluorescent Protein (gfpuv) from Escherichia coli

Background Transformed cells of Escherichia coli DH5-α with pGFPuv, induced by IPTG (isopropyl-β-d-thiogalactopyranoside), express the green fluorescent protein (gfpuv) during growth phases. E. coli subjected to the combination of selective permeation by freezing/thawing/sonication cycles followed by the three-phase partitioning extraction (TPP) method were compared to the direct application of TPP to the same culture of E. coli on releasing gfpuv from the over-expressing cells. Material and Methods Cultures (37°C/100 rpm/ 24 h; μ = 0.99 h-1 - 1.10 h-1) of transformed (pGFP) Escherichia coli DH5-α, expressing the green fluorescent protein (gfpuv, absorbance at 394 nm and emission at 509 nm) were sonicated in successive intervals of sonication (25 vibrations/pulse) to determine the maximum amount of gfpuv released from the cells. For selective permeation, the transformed previously frozen (-75°C) cells were subjected to three freeze/thaw (-20°C/ 0.83°C/min) cycles interlaid by sonication (3 pulses/ 6 seconds/ 25 vibrations). The intracellular permeate with gfpuv in extraction buffer (TE) solution (25 mM Tris-HCl, pH 8.0, 1 mM β-mercaptoethanol β-ME, 0.1 mM PMSF) was subjected to the three-phase partitioning (TPP) method with t-butanol and 1.6 M ammonium sulfate. Sonication efficiency was verified on the application to the cells previously treated by the TPP method. The intra-cell releases were mixed and eluted through methyl HIC column with a buffer solution (10 mM Tris-HCl, 10 mM EDTA, pH 8.0). Results The sonication maximum released amount obtained from the cells was 327.67 μg gfpuv/mL (20.73 μg gfpuv/mg total proteins – BSA), after 9 min of treatment. Through the selective permeation by three repeated freezing/thawing/sonication cycles applied to the cells, a close content of 241.19 μg gfpuv/mL (29.74 μg gfpuv/mg BSA) was obtained. The specific mass range of gfpuv released from the same cultures, by the three-phase partitioning (TPP) method, in relation to total proteins, was higher, between 107.28 μg/mg and 135.10 μg/mg. Conclusions The selective permeation of gfpuv by freezing/thawing/sonication followed by TPP separation method was equivalent to the amount of gfpuv extracted from the cells directly by TPP; although selective permeation extracts showed better elution through the HIC column.