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1.  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 $ 84 million 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 (~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, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources.
PMCID: PMC3471063  PMID: 23091360
2.  In LipL32, the Major Leptospiral Lipoprotein, the C Terminus Is the Primary Immunogenic Domain and Mediates Interaction with Collagen IV and Plasma Fibronectin ▿  
Infection and Immunity  2008;76(6):2642-2650.
LipL32 is the major leptospiral outer membrane lipoprotein expressed during infection and is the immunodominant antigen recognized during the humoral immune response to leptospirosis in humans. In this study, we investigated novel aspects of LipL32. In order to define the immunodominant domains(s) of the molecule, subfragments corresponding to the N-terminal, intermediate, and C-terminal portions of the LipL32 gene were cloned and the proteins were expressed and purified by metal affinity chromatography. Our immunoblot results indicate that the C-terminal and intermediate domains of LipL32 are recognized by sera of patients with laboratory-confirmed leptospirosis. An immunoglobulin M response was detected exclusively against the LipL32 C-terminal fragment in both the acute and convalescent phases of illness. We also evaluated the capacity of LipL32 to interact with extracellular matrix (ECM) components. Dose-dependent, specific binding of LipL32 to collagen type IV and plasma fibronectin was observed, and the binding capacity could be attributed to the C-terminal portion of this molecule. Both heparin and gelatin could inhibit LipL32 binding to fibronectin in a concentration-dependent manner, indicating that the 30-kDa heparin-binding and 45-kDa gelatin-binding domains of fibronectin are involved in this interaction. Taken together, our results provide evidence that the LipL32 C terminus is recognized early in the course of infection and is the domain responsible for mediating interaction with ECM proteins.
PMCID: PMC2423089  PMID: 18391007
3.  Production of Human Papillomavirus Type 16 L1 Virus-Like Particles by Recombinant Lactobacillus casei Cells 
Infections with human papillomavirus type 16 (HPV-16) are closely associated with the development of human cervical carcinoma, which is one of the most common causes of cancer death in women worldwide. At present, the most promising vaccine against HPV-16 infection is based on the L1 major capsid protein, which self-assembles in virus-like particles (VLPs). In this work, we used a lactose-inducible system based on the Lactobacillus casei lactose operon promoter (plac) for expression of the HPV-16 L1 protein in L. casei. Expression was confirmed by Western blotting, and an electron microscopy analysis of L. casei expressing L1 showed that the protein was able to self-assemble into VLPs intracellularly. The presence of conformational epitopes on the L. casei-produced VLPs was confirmed by immunofluorescence using the anti-HPV-16 VLP conformational antibody H16.V5. Moreover, sera from mice that were subcutaneously immunized with L. casei expressing L1 reacted with Spodoptera frugiperda-produced HPV-16 L1 VLPs, as determined by an enzyme-linked immunosorbent assay. The production of L1 VLPs by Lactobacillus opens the possibility for development of new live mucosal prophylactic vaccines.
PMCID: PMC1352212  PMID: 16391114
5.  Expression and characterization of HPV-16 L1 capsid protein in Pichia pastoris 
Archives of virology  2009;154(10):10.1007/s00705-009-0484-8.
Human papillomaviruses (HPVs) are responsible for the most common human sexually transmitted viral infections. Infection with high-risk HPVs, particularly HPV16, is associated with the development of cervical cancer. The papillomavirus L1 major capsid protein, the basis of the currently marketed vaccines, self-assembles into virus-like particles (VLPs). Here, we describe the expression, purification and characterization of recombinant HPV16 L1 produced by a methylotrophic yeast. A codon-optimized HPV16 L1 gene was cloned into a non-integrative expression vector under the regulation of a methanol-inducible promoter and used to transform competent Pichia pastoris cells. Purification of L1 protein from yeast extracts was performed using heparin–sepharose chromatography, followed by a disassembly/reassembly step. VLPs could be assembled from the purified L1 protein, as demonstrated by electron microscopy. The display of conformational epitopes on the VLPs surface was confirmed by hemagglutination and hemagglutination inhibition assays and by immuno-electron microscopy. This study has implications for the development of an alternative platform for the production of a papillomavirus vaccine that could be provided by public health programs, especially in resource-poor areas, where there is a great demand for low-cost vaccines.
PMCID: PMC3817616  PMID: 19756360
6.  A Transcriptomic View of the Proteome Variability of Newborn and Adult Bothrops jararaca Snake Venoms 
Snake bite is a neglected public health problem in communities in rural areas of several countries. Bothrops jararaca causes many snake bites in Brazil and previous studies have demonstrated that the pharmacological activities displayed by its venom undergo a significant ontogenetic shift. Similarly, the venom proteome of B. jararaca exhibits a considerable variation upon neonate to adult transition, which is associated with changes in diet from ectothermic prey in early life to endothermic prey in adulthood. Moreover, it has been shown that the Brazilian commercial antibothropic antivenom, which is produced by immunization with adult venom, is less effective in neutralizing newborn venom effects. On the other hand, venom gland transcripts of newborn snakes are poorly known since all transcriptomic studies have been carried out using mRNA from adult specimens.
Methods/Principal Findings
Here we analyzed venom gland cDNA libraries of newborn and adult B. jararaca in order to evaluate whether the variability demonstrated for its venom proteome and pharmacological activities was correlated with differences in the structure of toxin transcripts. The analysis revealed that the variability in B. jararaca venom gland transcriptomes is quantitative, as illustrated by the very high content of metalloproteinases in the newborn venom glands. Moreover, the variability is also characterized by the structural diversity of SVMP precursors found in newborn and adult transcriptomes. In the adult transcriptome, however, the content of metalloproteinase precursors considerably diminishes and the number of transcripts of serine proteinases, C-type lectins and bradykinin-potentiating peptides increase. Moreover, the comparison of the content of ESTs encoding toxins in adult male and female venom glands showed some gender-related differences.
We demonstrate a substantial shift in toxin transcripts upon snake development and a marked decrease in the metalloproteinase P-III/P-I class ratio which are correlated with changes in the venom proteome complexity and pharmacological activities.
Author Summary
Bothrops jararaca is one of the most abundant venomous snake species in Brazil. It is primarily a nocturnal and generalist animal, however, it exhibits a notable ontogenetic shift in diet, feeding mainly on arthropods, lizards, and amphibians (ectothermic prey) through its juvenile phase and on small mammals (endothermic animals) during adult life. Due to its broad geographical distribution, this species is responsible for the majority of the accidents by Bothrops genus in Brazil. Studies on envenomation cases with newborn and adult B. jararaca snakes have shown distinct patterns, mainly related to blood coagulation disorders, which seems to be prominent in accidents with newborn specimens. Moreover, it has been demonstrated that the Brazilian commercial antibothropic antivenom, which is produced by immunization with adult venom, is less effective in neutralizing newborn venom effects. In this study we analyzed the venom gland transcriptome of newborn snake specimens and compared the content of toxin transcripts with that of adult specimens. We demonstrate that upon B. jararaca development, its repertoire of mRNAs encoding toxins changes both qualitatively and quantitatively and these alterations are associated with the venom proteome profiles and pharmacological activities displayed by newborn and adult specimens.
PMCID: PMC3302817  PMID: 22428077
8.  Diversity of physiological cell reactivity to heat shock protein 60 in different mouse strains 
Cell Stress & Chaperones  2007;12(2):112-122.
Heat shock proteins (Hsp) are families of highly conserved molecules and immunodominant antigens in some infections and in autoimmune diseases. Some reports suggest that different regions of the Hsp60 molecule induce distinct immune responses. However, there are no reports comparing physiological T-cell reactivity to Hsp60 in mice. In this study, we have analyzed T-cell proliferation and cytokine production induced by Hsp60, under physiological conditions, in three mouse strains bearing distinct major histocompatibility complex (MHC) backgrounds. Proliferative response predominantly was found in C57BL/6 mice, mostly induced by N-terminal and intermediate Hsp60 peptides (P < 0.0001). Interferon-γ (IFNγ) production was broadly induced by different regions of Hsp60 in all three mouse strains, although response was focused in different peptide groups in each strain. We did not observe an exclusive Th1 or Th2 cytokine profile induced by any particular region of Hsp60. However, we identified a strain hierarchy in IL-10 production induced by Hsp60 peptides from different regions, mostly detected in C3H/HePas, and in BALB/c, but not in C57BL/6 mice. In contrast, IL-4 production only was induced by the intermediate and C-terminal region peptides in both C3H/HePas and BALB/c mice. Our data give original information on physiological cellular reactivity to Hsp60. We also have identified peptides with the capacity to induce the production of anti-inflammatory cytokines, bringing perspectives for their use in immunotherapy of chronic inflammatory diseases and allograft rejection.
PMCID: PMC1949334  PMID: 17688190
10.  Multiserotype Protection of Mice against Pneumococcal Colonization of the Nasopharynx and Middle Ear by Killed Nonencapsulated Cells Given Intranasally with a Nontoxic Adjuvant  
Infection and Immunity  2004;72(7):4290-4292.
Intranasal challenge of C57BL/6 mice with Streptococcus pneumoniae serotypes 6B, 14, and 23F produced colonization of the middle ear and NP. Intranasal vaccination with ethanol-killed nonencapsulated cells with adjuvant protected both sites. Of four nontoxic adjuvants tested, the cholera toxin B subunit was most effective and least nonspecifically protective.
PMCID: PMC427453  PMID: 15213177

Results 1-10 (10)