OBJECTIVETo provide the acute toxicity data of hygromycin B phosphotransferase (HPT) using recombinant protein purified from E. coli.

METHODSRecombinant HPT protein was expressed and purified from E. coli. To exclude the potential adverse effect of bacteria protein in recombinant HPT protein, bacterial control plasmid was constructed, and bacteria control protein was extracted and prepared as recombinant HPT protein. One hundred mice, randomly assigned to 5 groups, were administrated 10 g/kg, 5 g/kg, or 1 g/kg body weight of HPT or 5 g/kg body weight of bacterial control protein or phosphate-buffered saline (PBS) respectively by oral gavage.

RESULTSAll animals survived with no significant change in body weight gain throughout the study. Macroscopic necropsy examination on day 15 revealed no gross pathological lesions in any of the animals. The maximum tolerated dose (MTD) of HPT was 10 g/kg body weight in mice and could be regarded as nontoxic.

CONCLUSIONHPT protein does not have any safety problems to human health.

Animals ; Bacterial Proteins ; isolation & purification ; toxicity ; Escherichia coli ; genetics ; metabolism ; Female ; Male ; Mice ; Mice, Inbred Strains ; Phosphotransferases (Alcohol Group Acceptor) ; isolation & purification ; toxicity ; Recombinant Proteins ; isolation & purification ; toxicity ; Toxicity Tests, Acute

Animals ; Cell Transformation, Neoplastic ; Cloning, Molecular ; Hepacivirus ; genetics ; immunology ; pathogenicity ; Hepatitis C Antigens ; toxicity ; Liver Neoplasms, Experimental ; pathology ; virology ; Male ; Oncogenic Viruses ; pathogenicity ; RNA, Messenger ; toxicity ; Rats ; Rats, Sprague-Dawley ; Recombinant Fusion Proteins ; toxicity ; Viral Core Proteins ; toxicity ; Virion ; pathogenicity

OBJECTIVETo investigate the nasal epithelium toxicity of adjuvants and rHV2 nasal spary(HVS).

METHODCiliary movement were evaluated with in situ toad palate model; The histology assessment of nasal epithelium were carried out after long-lasting and repeated use of HVS.

RESULT AND CONCLUSIONAdjuvants included SDS, Brij 35, azone, lecithin, EDTA, menthol, nipagin and thiomersal were able to significantly inhibited the ciliary movement, while tween80, glycyrrhizic acid monoammonium salt, benzalkonium bromide, sodium benzoate and adhensive materials investigated had less influence on it. HVS was able to damaged the nasal epithelium, but this effect recovered soon after stopping administration. It was demonstrated that SDS, Brij 35, azone,lecithin, EDTA, menthol, nipagin and thiomersal. It had significant cilitoxity, while tween80, glycyrrhizic acid monoammonium salt, benzalkonium bromide, sodium benzoate and adhensive materials investigated had no significance; Chitosan co-administration with some adjuvants may make the cillitoxity severer; It is available that rHV2 be administered by nasal spary.

Adjuvants, Pharmaceutic ; administration & dosage ; toxicity ; Administration, Intranasal ; Animals ; Bufo bufo ; Chitosan ; administration & dosage ; toxicity ; Cilia ; drug effects ; Epithelium ; drug effects ; Female ; Hirudins ; administration & dosage ; toxicity ; Male ; Nasal Mucosa ; drug effects ; Palate ; drug effects ; Rabbits ; Recombinant Proteins ; administration & dosage ; toxicity

OBJECTIVETo clone and express the HIV-1B gp120 genes isolated at different organizations from a patient died of AIDS dementia complex (ADC) in eukaryotic cells.

METHODSUsing the genomic DNA isolated from peripheral lymphnodes, choroid plexus and occipital white matter from a patient died of ADC as the template, HIV-1B gp120 gene was amplified with PCR. After sequenced, HIV-1B gp120 was inserted into pcDNA3.1 (+) and recombinant expressing vector gp120/pcDNA3.1 (+) was constructed succeffuly confirming with sequencing. Then expressing vector was transfected into eukaryotic cells U87 using liposome transfection and expression of HIV-1B gp120 gene was assayed with indirect immunofluorescence.

RESULTSHIV-1B gp120 genes isolated from peripheral lymphnodes, choroid plexus and occipital white matter of the ADC patient were successfully cloned and recombinant expressing vector gp120/pcDNA3; 1 (+) could express envelope glycoprotein HIV-1B gp120 in U87 cells.

CONCLUSIONAll the HIV-1B gp120 gene isolated at the different organizations of the same ADC patient could express in U87 cells, which may supply a valuable basis for studying the neurotoxicity and neurotoxic mechanism of HIV-1 gp120 protein.

AIDS Dementia Complex ; virology ; Cloning, Molecular ; HIV Envelope Protein gp120 ; biosynthesis ; genetics ; toxicity ; Humans ; Recombinant Proteins ; biosynthesis ; Sequence Analysis, DNA

OBJECTIVEVerotoxin-producing Escherichia coli (VTEC) strains of serotype O157 : H7 have been implicated in a wide spectrum of diseases, including blood diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). To further explore the pathological role of verotoxin (VT) in HUS and other VTEC associated diseases, we investigated the effects of recombinant verotoxin 2 (rVT2) on the biological activity of neutrophils.

METHODSThe technique of flow cytometry, a fluorescent probe 2,7-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF/AM), and the assay of reduced cytochrome c to detect superoxide production were used in this study.

RESULTSgammaVT2 significantly inhibited spontaneous apoptosis in neutrophils. Neutrophils with prolonged survival due to gammaVT2 maintained various biological functions, such as the expression of adhesion molecules (shading CD62L and raising CD11b/CD18), adherence to human umbilical vein endothelial cells (HUVECs), and generation of superoxide (O(2)(-)).

CONCLUSIONProlongation of the functional life-span of neutrophils by gammaVT2 may accelerate inflammatory responses at sites of inflammation. This may play a crucial role in neutrophil-mediated tissue injury in HUS and other VTEC-associated diseases.

Apoptosis ; drug effects ; Cell Adhesion ; Endothelium, Vascular ; cytology ; Humans ; Neutrophils ; drug effects ; physiology ; Recombinant Proteins ; toxicity ; Shiga Toxin 2 ; toxicity ; Superoxides ; metabolism

OBJECTIVETo explore the biological activity of recombinant human single-chain antibody against amyloid beta peptide in vitro.

METHODSHuman single-chain antibody against amyloid beta peptide was obtained from recombinant bacteria. The antigen-binding activity of this antibody was measured by enzyme-linked immunosorbent assay (ELISA) and competitive ELISA. Human neuroblastoma SH-SY5Y cells were used as cell models to test the protective role of human single-chain antibody against amyloid beta peptide.

RESULTSRecombinant human single-chain antibody was mainly located in the insoluble inclusion bodies of bacteria. The antibody was dissolved by urea and purified by metal affinity chromatography as active form to bind synthetic amyloid beta peptide 40 or amyloid beta peptide 42. The improvement of the survival rates of human neuroblastoma cells was significantly superior in amyloid peptide 42 plus equimolar antibody group than in amyloid peptide 42 group (P < 0.05), and was significantly superior in the amyloid peptide 40 plus equimolar antibody group than in amyloid peptide 40 group (P < 0.01).

CONCLUSIONThe recombinant human single-chain antibody against beta amyloid peptide 40 from E. coli can partially inhibit the neurotoxicity effect of amyloid beta peptide in vitro.

Amyloid beta-Peptides ; immunology ; metabolism ; toxicity ; Cell Line, Tumor ; Cell Survival ; drug effects ; Humans ; Peptide Fragments ; metabolism ; toxicity ; Protein Binding ; Recombinant Proteins ; pharmacology ; Single-Chain Antibodies ; pharmacology

Escherichia coli heat-labile enterotoxin (LT) is composed of catalytic A and non-catalytic homo-pentameric B subunits and causes diarrheal disease in human and animals. In order to produce a nontoxic LT for vaccine and adjuvant development, two novel derivatives of LT were constructed by a site-directed mutagenesis of A subunit; Ser63 to Tyr63 in LTS63Y and Glu110, Glu112 were deleted in LT delta 110/112. The purified mutant LTs (mLTs) showed a similar molecular structural complex as AB5 to that of wild LT. In contrast to wild-type LT, mLTs failed to induce either elongation activity, ADP-ribosyltransferase activity, cAMP synthesis in CHO cells or fluid accumulation in mouse small intestine in vivo. Mice immunized with mLTs either intragastrically or intranasally elicited high titers of LT-specific serum and mucosal antibodies comparable to those induced by wild-type LT. These results indicate that substitution of Ser63 to Tyr63 or deletion of Glu110 and Glu112 eliminate the toxicity of LT without a change of AB5 conformation, and both mutants are immunogenic to LT itself. Therefore, both mLTs may be used to develop novel anti-diarrheal vaccines against enterotoxigenic E. coli.
Amino Acid Substitution ; Animal ; Bacterial Toxins/toxicity* ; Bacterial Toxins/metabolism ; Bacterial Toxins/immunology* ; Bacterial Toxins/genetics ; CHO Cells ; Cyclic AMP/metabolism ; Enterotoxins/toxicity* ; Enterotoxins/metabolism ; Enterotoxins/immunology* ; Enterotoxins/genetics ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli*/metabolism ; Escherichia coli*/genetics ; Female ; Hamsters ; IgA, Secretory/blood ; Ileum/metabolism ; Immunity, Mucosal ; Mice ; Mice, Inbred BALB C ; Mutagenesis, Site-Directed ; NAD+ ADP-Ribosyltransferase/metabolism ; Recombinant Proteins/toxicity ; Recombinant Proteins/metabolism ; Recombinant Proteins/immunology ; Recombinant Proteins/chemistry

OBJECTIVETo investigate the penetrating ability of fusion protein PEP-1-EGFP with human umbilical vein endothelial cells.

METHODSTwo prokaryotic expression plasmids pET15b-EGFP and pET15b-PEP-1-EGFP were constructed and transformed into E. coli BL21 (DE3) to express EGFP and fusion protein PEP-1-EGFP, respectively. The expressed EGFP and PEP-1-EGFP were purified with Ni(2+) -resin affinity chromatography, and their capabilities of transduction into human umbilical vein endothelial cells were evaluated. The time- and dose-dependent transduction of the fusion protein PEP-1-EGFP and its stability in the human umbilical vein endothelial cells were observed. The toxicity of the fusion protein PEP-1-EGFP was detected by MTT method.

RESULTSEGFP failed to be transduced into human umbilical vein endothelial cells, whereas PEP-1-EGFP fusion protein was transduced into cells shortly in 5 minutes. Its transduction was time- and dose-dependent and the fluorescence in the cells were detected even 27 hours later. No cytotoxicity of the fusion protein PEP-1-EGFP to human umbilical vein endothelial cells was detected even when the dose reached up to 200 micromol/L.

CONCLUSIONPEP-1-EGFP fusion protein can efficiently transduce the target protein into human umbilical vein endothelial cells, which provides a basis for future researches on the transduction of antioxidant enzymes mediated by the cell-penetrating peptide, PEP-1, in ischemia-reperfusion injury therapy.

Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Green Fluorescent Proteins ; metabolism ; Humans ; Peptides ; metabolism ; Protein Transport ; Recombinant Fusion Proteins ; metabolism ; toxicity ; Umbilical Veins ; cytology

An expression plasmid carrying anthrax protective antigen (PA) gene was constructed, which has an OmpA signal sequence attached to the 5' end of PA gene. The plasmid was transformed into E. coli and induced to express recombinant PA (rPA) . The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ion-exchange, hydrophobic interaction chromatography, and gel filtration, about 15 mg of 95 % pure rPA was obtained from 1-liter culture. The bioactivity of rPA was proved by in vitro cytotoxicity assay. The polyclonal antiserum from rabbits immunized with rPA could inhibit the action of anthrax lethal toxin in vitro, which suggests that antibodies against rPA can provide high passive protection against anthrax. The results reported here may be helpful to develop a safe and efficacious recombinant PA vaccine against anthrax.
Amino Acid Sequence ; Animals ; Anthrax Vaccines ; immunology ; Antigens, Bacterial ; chemistry ; genetics ; immunology ; toxicity ; Bacterial Toxins ; chemistry ; genetics ; immunology ; toxicity ; Base Sequence ; Mice ; Molecular Sequence Data ; Plasmids ; Rabbits ; Recombinant Proteins ; biosynthesis ; immunology ; Vaccines, Synthetic ; immunology

OBJECTIVETo investigate the protective effect of recombinant human N-terminal lipopolysaccharide binding protein in mice challenged with LPS.

METHODSSeventy male Kunming mice were randomly divided into 3 groups, i.e. LPS challenge (Injection of LPS into abdominal cavity, n = 21); tLBP protection (Injection of LPS and tLBP into abdominal cavity, n = 21) and control (Injection of normal saline into abdominal cavity, n = 8) groups. The blood samples and tissue samples of the liver and lungs were harvested on 15 and 30 minutes and 1, 3, 6, 12 and 24 hours after the injection. The serum contents of ALT and TNF-alpha were determined by biochemical velocity analysis and RIA method, respectively. The pathomorphological changes in the liver and pulmonary tissue were examined under light microscope (LM). The mortality rate of ten mice each was observed within 24 hours after the injection of tLBP + 400 ng LPS or 400ng LPS.

RESULTSThe ALT content of tLBP group reached the peak level at 12 post-injection hour (PIH) (41.00 +/- 4.58), but it was significantly lower than that in LPS group in which it peaked at 6PIH (99.50 +/- 62.63) (P < 0.01). The TNF-alpha content in tLBP and LPS group was lower than that in LPS group, and both reached the peak level at 3 PIH (35.96 +/- 7.33). Compared with those in LPS, injury to hepatocytes in tLBP group was obviously milder without scattered necrosis. The pulmonary congestion in tLBP group was abated, and the inflammatory exudation in the alveoli was evidently less than that in LPS group. There were 9 out of 10 mice died in the LPS challenge group, while only 3 out of 10 mice died during 24 hours after LPS injection in tLBP protection group.

CONCLUSIONPreliminary results indicated that recombinant human tLBP might possess biological activity with a potential protection effect in LPS challenged mice.

Acute-Phase Proteins ; Animals ; Carrier Proteins ; therapeutic use ; Lipopolysaccharides ; toxicity ; Liver ; drug effects ; pathology ; Lung ; drug effects ; pathology ; Male ; Membrane Glycoproteins ; Mice ; Random Allocation ; Recombinant Proteins ; pharmacology ; Tumor Necrosis Factor-alpha ; analysis