Based on the different permeability of DNA-intercalant dyes YO-PRO-1(YP) and propidium iodide (PI) to the membrane of viable, apoptotic and necrotic cells, cell samples were stained with 4?mol/L YP and 4?g/ml PI for 10 min, and the fluorescence intensity of both YP and PI were measured by fluorometer at Ex/Em wavelength of 485/538nm and 530/590nm, respectively. The correlation between YP fluorescence intensity and the apoptotic cell number was confirmed by fluorescence microscope and linear regression(r=0.999,P

The synthetic gene with 1640bp encoding for the anti-CD3/anti-CD20 bispecific single-chain antibody was designed and obtained by SOE (splicing by overlap extension) PCR. The cDNA was cloned into Flp-In expression vector pcDNA5/FRT and transfeced into Flp-In CHO cells to generate a stable expression cell line with a capacity for expressing anti-CD3/anti-CD20 bispecific single-chain antibody at 300 microg/L. The protein, which had a molecular weight of about 70 kD,was purified by Ni-NTA affinity chromatography and identified by SDS-PAGE and Western-blot analysis. Immunofluorescence assay and cellular rosetting showed that it can react specifically on Jurkat (CD3+) and Ramous (CD20+) cells. The lysis of human PBL against CD20-positive lymphoma Ramous cells in the presence of the anti-CD3/anti-CD20 bispecific single-chain antibody can observed by microscope. All these results would lighten the further study of its biological functions in vitro and in vivo.
Animals ; Antibodies, Bispecific ; biosynthesis ; genetics ; immunology ; Antibodies, Monoclonal ; immunology ; Antigens, CD20 ; immunology ; CD3 Complex ; immunology ; CHO Cells ; Cricetinae ; Cricetulus ; Humans ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Lymphoma, B-Cell ; metabolism ; Recombinant Proteins ; Transfection ; Tumor Cells, Cultured

By using the cell density, cell viability, size distribution of cell aggregates,specific consumption rate of glucose (q_ glc ), specific production rate of lactate (q_ lac ), lactate transform rate (Y_ lac/glc ) and amino acids utilization as the evaluation indexes, the growth and metabolism of HEK293 cells under carrier-free immobilization culture mode were examined and compared with those of HEK293 cells cultured in static tissue flasks. It was found that HEK293 cells grown as suspended cell aggregates in spinner flasks maintained the basic growth and metabolism characteristics of HEK293 cells in stationary anchored culture, and HEK293 cells under carrier-free immobilization culture mode as suspended aggregates in stirred bioreactor facilitate perfusion performance and increase unit productivity. Cultivation of HEK293 cells in carrier-free immobilization culture mode has potential for further improving mammalian cells culture technique.

By using the size distribution of cell aggregates, viable cell density, cell viability, specific consumption rate of glucose (q(glc)), specific production rate of lactate (q(lac)) and lactate transform rate (Y(lac/glc)) as the evaluation indexes, the effects of hydrodynamic on aggregates formation, growth and metabolism of HEK293 cells in suspension culture were examined in 250mL spinner-flasks by setting the agitation rates at 25, 50, 75 and 100r/min, respectively. It was found that agitation plays an important role in HEK293 cell aggregates formation and cell aggregates size distribution. After 7d cultivation in spinner-flasks operated at 50r/min and 75r/min, the average diameter of HEK293 cell aggregates was 201 microm and 175 microm, respectively, with the fraction of aggregates larger than 225 microm less than 10%. The cell viability was kept above 90% with the metabolic indexes, including q(glc), q(lac) and Y(lac/glc) kept constant. These results demonstrated that hydrodynamic derived from the proper agitation play a decisive role in controlling the formation and size distribution of HEK293 cell aggregates, and provided sufficient mass transfer to support the normal growth and metabolism of HEK293 cells in suspended aggregates.
Bioreactors ; Cell Aggregation ; Cell Culture Techniques ; instrumentation ; Cell Line ; Cell Proliferation ; Humans ; Kinetics

After having successfully constructed and expressed the gene of the anti-CD3/anti-CD20 bispecific single-chain antibody (bscCD3 x CD20), here we analyzed its in vitro bioactivity of mediating the lysis of Ramous human B-lymphoma cells in the presence of T-enriched human peripheral blood lymphocytes (PBL). Obvious opoptosis characters were observed by Annexin V/PI(AV/PI) stained and scanning electron microscope. As evaluated by non-radioactive cytotoxity assay, the bscCD3 x CD20 showed potent bioactivity of mediating human B-lymphoma cells lysis in the presence of T-enriched human PBL. The potency of cytotoxicity depended on the ratios of effect cells to target cells (E:T) used. Further, the antibody showed a dose and time-dependent effect on mediating Ramous cells lysis. The specific lysis reached about 87.3% at an antibody concentration of 5microg/mL and E:T used at 10:1. Clear changes in apoptogenes expression profiles were detected by apoptosis gene array after Ramous cells were treated with the antibody and PBL. Among the upregulated apoptogenes, ATM and P53 showed an increase of 187 times and 15 times respectively, which suggested that ATM-p53 pathway may be the main apoptosis way of Ramous cells induced by T cells in the presence of the bscCD3 x CD20.
Antibodies, Bispecific ; immunology ; Antigens, CD20 ; immunology ; Apoptosis ; immunology ; CD3 Complex ; immunology ; Humans ; Lymphoma, B-Cell ; immunology ; pathology ; T-Lymphocytes, Cytotoxic ; immunology ; Tumor Cells, Cultured

Using the amino acids 1-147 of the yeast transcriptional activator GAL4 as the DNA-binding domain and four tandem repeats of the 12-aa peptide (DALDDFDLDMLG) of the herpesvirus as the activation domain, an artificial transcription factor, GVP4,was constructed via the linkage of the nuclear localization signal sequence of SV40. And then, GVP4 was cloned into expression vector pcDNA3 . 1/Hygro ( + ) . Various amounts of targeting sites of artificial transcription factor were linked to the upstream of promoter CMV in exogenous gene expression vector pcDNA3.1 ( + ) that separately harbored EGFP cDNA and t-PA cDNA.The CHO cells were then co-transfected with GVP4 expression vector and EGFP or t-PA expression vector. The effect of GVP4 on exogenous gene expression was evaluated by measuring the fluorescence intensity of EGFP in CHO cells and the concentration of t-PA in the supernatant. GVP4 showed positive effect on the enhancement of exogenous gene expression in CHO cells integrated with targeting sites of artificial transcription factor. And, CHO cells integrated with 10 targeting sites of GVP4 was more favorable to foreign gene expression, which resulted in 2-3-fold increase in both EGFP and t-PA expressions. These results indicated that artificial transcription factor is potent in the enhancement of exogenous gene expression in mammalian cells.
Amino Acid Sequence ; Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Flow Cytometry ; Gene Expression Regulation ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; metabolism ; Tissue Plasminogen Activator ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transcriptional Activation ; Transfection

OBJECTIVETo evaluate the effect of snail control through soil pasting mixed with niclosamide.

METHODSFour sites were selected in different epidemic areas in Sichuan province. Soil pasting mixed with niclosamide was carried on, and the dosage was 0 g/m2, 4 g/m2, 6 g/m2, 8 g/m2 and 10 g/m2 respectively. The mortality rate of snail and the density of snail were observed after 7, 15, 30, 90 and 180 days.

RESULTSThe mortality rate of snail was more than 43.3% in blank group after 30 days. The mortality rate of snail was from 75.3% to 100.0% at 4 g/m2 group after 30 days. The mortality rate of snail in 4 g/m2 group was significantly higher than that in the blank group (chi2 = 31.27, P < 0.05). There was no significant difference in the mortality rate of snail among all study groups (chi2 = 1.07, P > 0.05). The decrease rate of snail density was more than 90%. The mortality rate of snail was about 30% higher in Chantu group than Qutu group. The unit cost of Pasting-Mixing Drug with Soil was from 5 to 7 times of spray method, but the total cost was similar for the. two methods at the endpoint of the snail control.

CONCLUSIONThe effect of soil pasting mixed with niclosamide is good, and the dosage of 4-6 g/m2 is suggested in snail control.

Animals ; Molluscacides ; Niclosamide ; Pest Control ; Schistosomiasis ; epidemiology ; prevention & control ; Snails ; Soil

OBJECTIVETo evaluate the protective efficacy of plague subunit vaccine, BALB/c mice, guinea pigs and rabbits were used in this study.

METHODSGroups of mice (10 per group), guinea pigs (14 per group) and rabbits (6 per group) were immunized with F1 + rV270 vaccine, EV76 vaccine and alum adjuvant by intramuscular route, respectively. Serum antibody titres of mice, guinea pigs and rabbits were determined by ELISA and the immunized animals were challenged with 10(6) CFU of Y. pestis strain 141 at the 8th week after the primary immunization.

RESULTSThe immunized mice, guinea pigs or rabbits with subunit vaccine developed anti-F1 IgG titre of 41 587.3 +/- 2.1, 11 543.7 +/- 2.1 or 522.4 +/- 22.4 and elicited statistical anti-F1 IgG titre difference among them (F = 17.58, P < 0.01). The immunized mice, guinea pigs or rabbits with subunit vaccine had anti-rV270 IgG titre of 15 748.7 +/- 1.6, 12.6 +/- 1.4 or 1648.0 +/- 5.0 and induced statistical anti-rV270 IgG titre difference among them (F value was 16.34, P < 0.01). There was significant anti-F1 IgG titre difference among mice, guinea pigs and rabbits immunized with EV76 vaccine that developed anti-F1 IgG titre of 913.4 +/- 4.5, 937.0 +/- 2.0 or 342.0 +/- 12.0 (F = 23.67, P < 0.01), whereas the immunized mice, guinea pigs and rabbits with EV76 vaccine developed anti-rV270 IgG titre of 12.0 +/- 1.0, 447.0 +/- 10.0, 40.0 +/- 11.0 and there was no anti-rV270 IgG titre difference between them (F = 2.20, P = 0.1314). The immunized mice with subunit vaccine developed significantly higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 30.57 and 19.04, respectively, P < 0.01), and there were no anti-F1 IgG titre differences between the immunized guinea pigs and rabbits (q = 0.04, P = 0.8485). The immunized mice with subunit vaccine developed significantly higher anti-rV270 IgG titres than immunized guinea pigs and rabbits (q value was 27.10 and 19.49, respectively, P < 0.01), and there were no anti-rV270 IgG titre differences between the immunized guinea pigs and rabbits with the subunit vaccine (q = 0.25, P = 0.6187). The immunized mice with EV76 elicited higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 40.67 and 29.10, respectively, P < 0.01), whereas there was no difference of F1 IgG titer between immunized guinea pigs and rabbits (q = 0.06, P = 0.8098). The immunized mice, guinea pigs and rabbits with subunit vaccine provided 100% (10/10), 86% (12/14) and 100% (5/5) protection against 10(6) CFU Y. pestis of challenge, respectively. The immunized mice, guinea pigs and rabbits with EV76 vaccine gave 100% (6/6), 93% (13/14) and 100% (6/6) protection against 10(6) CFU Y. pestis of challenge respectively.

CONCLUSIONBALB/c mice is the best small animal model for valuation of protective efficacy of plague subunit vaccine. The guinea pigs showed a high individual variation for this purpose. The rabbits can be used as an alternative model for evaluating plague subunit vaccine.

Animals ; Antibodies, Bacterial ; blood ; Dose-Response Relationship, Immunologic ; Female ; Guinea Pigs ; Immunization ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Models, Animal ; Plague ; prevention & control ; Plague Vaccine ; immunology ; Rabbits ; Vaccines, Subunit ; immunology

OBJECTIVETo study the relationship between the levels of erythropoietin (EPO) in serum and brain injury in preterm infants.

METHODSThree hundred and four preterm infants (gestational age: 28-34 weeks) born between October 2014 and September 2015 were enrolled in this study. Brain injury was diagnosed using cerebral ultrasound and MRI. The levels of EPO, S100 protein, neuron-specific enolase (NSE) and myelin basic protein (MBP) in serum were detected using ELISA. To compare the incidence of brain injury in different serum EPO levels in preterm infants, and the relationship between brain injury and serum EPO levels was analyzed.

RESULTSThe incidence rate of brain injury in preterm infants was 41.1% (125/304). The incidence rate of brain injury in the low EPO level group was significantly higher than that in the middle-high EPO level groups (P<0.01). The serum levels of S100 protein, NSE, and MBP in the brain injury groups were significantly higher than in the control group (P<0.01). The serum EPO levels were negatively correlated with serum S100 protein concentration and NSE levels (P<0.05). According to the multiple logistic regression analysis, low gestational age, low birth weight, asphyxia, prolonged mechanical ventilation, anemia and low serum EPO levels were the risk factor for brain injury in preterm infants.

CONCLUSIONSThere is a higher incidence rate of brain injury in preterm infants with lower serum EPO levels. The serum EPO levels may be correlated with brain injury in preterm infants.

Brain Injuries ; blood ; epidemiology ; Erythropoietin ; blood ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; blood ; Male ; Myelin Basic Protein ; blood

OBJECTIVELcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study.

METHODSA new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a. After Co(2+) affinity chromatography, a purification strategy was developed by cleavage of His tag on column, following Sephacryl S-200HR column filtration chromatography.

RESULTSRemoval of His tag by thrombin, enterokinase and factor Xa displayed a yield of 99.5%, 32.4% and 15.3%, respectively. Following Sephacryl S-200HR column filtration chromatography, above 97% purity of rV270 protein was obtained. Purified rV270 that was adsorbed to 25% (v/v) Al(OH)₃ adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to rV270 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 10⁶ CFU of Y. pestis virulent strain 141.

CONCLUSIONThe completely authentic rV270 protein can be prepared by using enterokinase or factor Xa, but they exhibited extremely low cleavage activity to the corresponding recognition site. Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy. The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.

Amino Acid Sequence ; Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; genetics ; immunology ; Blotting, Western ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Female ; Genetic Vectors ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Plague ; immunology ; prevention & control ; Plague Vaccine ; genetics ; immunology ; Plasmids ; Pore Forming Cytotoxic Proteins ; genetics ; immunology ; Protein Engineering ; methods ; Recombinant Fusion Proteins ; genetics ; immunology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Survival Analysis ; Vaccines, Subunit ; genetics ; immunology ; Yersinia pestis ; growth & development ; immunology