Using of two-step integrating technology, transducted the H and L chain gene of humanized Fab fragment of anti-HB-sAg antibody into the genome of methylotropic yeast P. pastoris. Constructed a engineering yeast to produce humanized Fab fragment of the anti-HBsAg antibody. The Fab fragment was efficiently secreted into the medium at a concentration of 50-80 mg/L. The Fab fragment was purified from culturing supernatant of the recombinant yeas by affinity chromatography. The ELISA analysis showed the high affinity of the expressed humanized Fab fragment to the HBsAg.
Chromatography, Affinity ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; Hepatitis B Antibodies ; biosynthesis ; genetics ; isolation & purification ; Hepatitis B Surface Antigens ; immunology ; Humans ; Immunoglobulin Fab Fragments ; biosynthesis ; genetics ; isolation & purification ; Pichia ; genetics ; Recombinant Proteins ; biosynthesis ; isolation & purification

In order to produce recombinant human anti-HBsAg Fab antibody in Pichia pastoris, the recombinant yeast was fermented using fed-batch system in a 30 L bioreactor. The fermentation temperature was 30 degrees C, the pH was 5.0 approximately 5.3, and the DO was 20% approximately 30%. The recombinant Fab antibody was purified from crude culture supernatant by ion exchange and analyzed by SDS-PAGE and western blot and ELISA. When the absorbance (OD600) of broth reach 300 at the end of fed-batch phase, the induced phase was initiated. The results showed that recombinant human anti-HBsAg Fab antibody was high-level expressed in recombinant Pichia pastoris using a fed-batch fermentation system. Both chains of the Fab were successfully expressed upon methanol induction. After 192 h of induction, the expression level of recombinant Fab (soluble) reached 412 mg/L. The recombinant Fab antibody was purified effectively by ion-exchange chromatography from the fermentation supernatant to a purity of 95%. And the affinity activities of the purified recombinant Fab antibdy and fermentation supernatant were detected, and both of them showed high affinity activities. The results demonstrated that recombinant human anti-HBsAg Fab antibody could be high level produced by fed-batch fermentations in Pichia pastoris. Which can be efficiently used in industrial production.
Fermentation ; Hepatitis B Antibodies ; biosynthesis ; isolation & purification ; Hepatitis B Surface Antigens ; immunology ; Humans ; Immunoglobulin Fab Fragments ; biosynthesis ; isolation & purification ; Pichia ; genetics ; Recombinant Proteins ; biosynthesis ; isolation & purification

The cytoplasm of E. coli is a reducing environment where cysteines do not engage in disulfide bonds. Any disulfide bonds that do appear are rapidly reduced through the action of disulfide reducing enzymes such as thioredoxin and glutaredoxin. To study the influence of E. coli cytoplasm on the solubility of recombinant proteins produced in it, bovine fibroblast growth factor (BbFGF), with single disulfide bond, and anti-HBsAg single-chain Fv (HBscFv), with two disulfide bonds, were selected as the pattern molecules of simple protein and complex protein, respectively. pJN98-BbFGF, a BbFGF expressing plasmid based on the vector pET3c, was constructed and transformed into normal host BL21(DE3) and a reductase deficient strain, E. coli Origami(DE3). At the same time, pQE-HBscFv, a HBscFv expressing plasmid was constructed and transformed into M15 [pREP4] and Origami(DE3). The recombinant BbFGF and HBscFv were produced in 2 types of bacteria and their solubilities and bioactivities were determined, respectively. It was found that the majority of BbFGF had formed inclusion body in the cytoplasm of BL21 (DE3) and all of them turned into soluble protein in Origami(DE3). It was also found the productivity of BbFGF in Origami (DE3) was 5% - 10% of the total protein and the value was 15% - 23% in BL21(DE3). BbFGFs produced in 2 recombinant bacteria were purified by cation exchange and heparin affinity chromatography. MTT assay revealed that the bioactivity of BbFGF purified from Origami(DE3) was higher than its counterpart from BL21(DE3). The ED50 of BbFGFs from different bacteria was 1.6ng/mL and 2.2ng/mL, respectively. As far as HBscFvs, both of them formed inclusion body in the cytoplasm of M15 [pQE-HBscFv] and Origami [pQE-HBscFv]. The inclusion body was solubilized in 6mol/L GuHCl, purified with a His-Trap column and then refolded by dialysis step-by-step against buffers containing downtrend concentration of GuHCl. Indirect ELISA was applied to determine the HBsAg binding activity of HBscFvs. It was found there was no obvious difference between the bioactivity of refolded HBscFvs produced from 2 recombinant bacteria. On the other hand, the supernatant of Origami [pQE-HBscFv] lysate displayed weak bioactivity and its counterpart from M15 [pQE-HBscFv] displayed without any bioactivity. The soluble HBsFv in the cytoplasm of Origami [pQE-HBscFv] was purified by cation exchange and immobilized metal affinity chromatography (IMAC) and the yield was 1 - 2mg/L. Those results suggested that modification of the redox environment of E. coli cytoplasm greatly improved the solubility of recombinant disulfide-bonded proteins produced in it. In the next step, we had like to co-express of molecular chaperones or refoldase to raise the yield of soluble recombinant proteins, as well as optimizing the culture condition of the "oxidizing" E. coli.
Animals ; Antibodies ; genetics ; immunology ; metabolism ; Cattle ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; enzymology ; genetics ; metabolism ; Escherichia coli Proteins ; genetics ; Fibroblast Growth Factors ; genetics ; metabolism ; Genetic Vectors ; genetics ; Hepatitis B Surface Antigens ; immunology ; Inclusion Bodies ; chemistry ; metabolism ; Oxidoreductases ; genetics ; Plasmids ; genetics ; Protein Engineering ; Recombinant Proteins ; chemistry ; genetics ; metabolism ; Solubility

To express and secrete native HBscFv (anti-HBsAg single-chain Fv) in P. pastoris, HBscFv was amplified from plasmid pGEM-HBscFv, and then sub-cloned into expression vector pPICZalphaA. The resulting plasmid pPIC-HBscFv was linearized and transformed into P. pastoris GS115. The recombinant Pichia strains, identified by direct PCR and Zeocin-resistant screening of Pichia transformants, were cultured and induced with methanol. It was found that recombinant HBscFv, lead by alpha-factor, could be secreted into the culture supernatant to a level of 80mg/L. The bioactivity of Pichia produced HBscFv was confirmed by indirect ELISA, which also suggested that the bioactivity of HBscFv in the culture supernatant reached its peak in 72h and decreased in the late-stage of the induction. PAS staining suggests that HBscFv produced by yeast is poorly glycosylated or none-glycosylated protein.
Blotting, Western ; Electrophoresis, Polyacrylamide Gel ; Hepatitis B Surface Antigens ; immunology ; Humans ; Pichia ; genetics ; metabolism ; Polymerase Chain Reaction ; Single-Chain Antibodies ; genetics ; immunology ; metabolism

In Taiwan, high-risk patients have been identified and tested for preventing community spread of COVID-19. Most sample collection was performed in emergency departments (EDs). Traditional sample collection requires substantial personal protective equipment (PPE), healthcare professionals, sanitation workers, and isolation space. To solve this problem, we established a multifunctional sample collection station (MSCS) for COVID-19 testing in front of our ED. The station is composed of a thick and clear acrylic board (2 cm), which completely separates the patient and medical personnel. Three pairs of gloves (length, 45 cm) are attached and fixed on the outside wall of the MSCS. The gloves are used to conduct sampling of throat/nasal swabs, sputum, and blood from patients. The gap between the board and the building is only 0.2 cm (sealed with silicone sealant). ED personnel communicate with patients using a small two-way broadcast system. Medical waste is put in specific trashcans installed in the table outside the MSCS. With full physical protection, the personnel conducting the sampling procedure need to wear only their N95 mask and gloves. After we activated the station, our PPE, sampling time, and sanitization resources were considerably conserved during the 4-week observation period. The MSCS obviously saved time and PPE. It elevated the efficiency and capacity of the ED for handling potential community infections of COVID-19.
Betacoronavirus ; Clinical Laboratory Techniques ; Coronavirus Infections ; diagnosis ; epidemiology ; Emergency Service, Hospital ; organization & administration ; Humans ; Mass Screening ; methods ; Pandemics ; Personal Protective Equipment ; supply & distribution ; Pneumonia, Viral ; diagnosis ; epidemiology ; Taiwan ; epidemiology