CHO-K1 Cell Line Research Articles

Production of a new variant of soluble trimer Env of HIV-1 CRF63_02A6 SOSIP.664

Introduction. Obtaining stabilized recombinant HIV-1 Env trimers that have a close to the native conformation is one of the directions in the field of development of vaccines against HIV-1. The aim of the study was to obtain and characterize the stabilized trimer Env of HIV-1 SOSIP.664 based on the circulating genetic variant of the recombinant form CRF63_02A6. Materials and methods. Bioinformatics resources were used to design the trimer Env gene based on the HIV-1 recombinant genetic variant CRF63_02A6. The designed gene was synthesized and cloned as part of an integration plasmid vector. A stable producer of trimer Env was obtained by transfection of the CHO-K1 cell line using the developed plasmid vector. Purification of the protein complex was performed using affinity chromatography and gel filtration. Antigenic properties of trimer Env were studied using immunochemical analysis using broadly neutralizing HIV-1 monoclonal antibodies (bnAbs). Results. A new variant of the stabilized trimer Env of the surface glycoprotein of the recombinant form CRF63_02A6 HIV-1 SOSIP.664 was designed, including additional stabilizing modifications. Based on the CHO-K1 cell line, a stable producer was obtained and a purification protocol for the designed trimer Env was developed. It was found that the trimer Env CRF63_02A6 SOSIP.664 is effectively recognized by bnAbs 2G12, VRC01 and PGT126. Conclusion. The obtained results indicate the prospects for further study of the structural features of the trimer Env CRF63_02A6 SOSIP.664, as well as its immunogenicity and the possibility of using it as a vaccine antigen.

In vitro toxicity of microalgae species of the phyla chlorophyta and ochrophyta in CHO-k1 and HEP G2 cells for potential use in human nutrition

Microalgae are a promising component to enhance human nutrition, but to date only a few species have been authorized to be used in human nutrition. In this study, the in vitro toxicity of eight novel microalgae strains (Botryococcus braunii, Chlorococcum novae-angliae, Microchloropsis salina, Myrmecia bisecta, Stichococcus sp. Tetraselmis suecica, Tetradesmus obliquus and Spongiochloris minor) selected for their potential for human nutrition was investigated. N-hexane, acetone, ethanol and aqueous extracts of the lyophilized biomass were tested in the CHO-k1 and HEP G2 cell lines at concentrations of up to 1.81 mg ml-1 extracted biomass per well. None of the tested microalgae extracts reached values defined as a significant cytotoxic effect (IC50 < 0.02 mg ml-1). The highest cytotoxic effects were measured for Stichococcus sp. in both cell lines with IC50 values of 0.17 mg ml-1 for the acetone extract in CHO-k1 cell culture and 0.18 mg ml-1 for the acetone extract in HEP G2 cell culture. Most cytotoxic effects occurred with the acetone and ethanol extracts, while the water and n-hexane extracts showed almost no measurable cytotoxic effects. Only Tetraselmis suecica showed no cytotoxic effect under the chosen conditions in both tested cell lines, marking this microalgae as particularly interesting for further investigations into its use in human nutrition.

Anticancer properties and prevention of metabolic syndrome by probiotic-enriched powdered human milk

This work aimed to develop a novel formulation based on human milk (HM) enriched with a probiotic formulation comprised of Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R and Lactobacillus rhamnosus CLR2 and to evaluate in vitro and in vivo anticancer properties and its impact on the prevention of risk factors of metabolic syndrome (MetS). In vitro studies were conducted on Hepa-1c1c7, HT-29, and CHO-K1 cell lines to assess the antiproliferative and anticancer properties of HM and probiotics. The in vivo study was conducted with 28 male Wistar rats fed a high-fat diet (HFD). Rats were daily force-fed with HM and HM + probiotics or water for 8 weeks. Inflammation and oxidative stress were monitored through blood cytokines and kidney investigation. Body weight and blood glucose were recorded throughout the study. The results showed that HM had antiproliferative properties and caused apoptosis of intestinal tumoral cells. Quinone reductase (QR) was induced up to 1.8x in Hepa-1c1c7 cell line demonstrating chemotherapeutic potential. HM enriched with probiotics reduced weight gain by 10% while renal oxidative damages were reduced by up to 97%. Blood insulin and Plasminogen Activator Inhibitor-1 (PAI-1) levels were also significantly reduced. The study showed that HM had antiproliferative and chemopreventive properties on cancer cell lines. The in vivo experiment suggests that the development of a formulation based on HM powder enriched with probiotics could be used to modulate the rate of inflammation and oxidative damage to tissues, thus reducing the risk of obesity-related diseases.

Target-based discovery of antagonists of the tick (Rhipicephalus microplus) kinin receptor identifies small molecules that inhibit midgut contractions.

A GPCR (G protein-coupled receptor) target-based approach was applied to identify antagonists of the arthropod-specific tick kinin receptor. These small molecules were expected to reproduce the detrimental phenotypic effects that had been observed in Rhipicephalus microplus females when the kinin receptor was silenced by RNA interference. Rhipicephalus microplus, the southern cattle tick, cattle fever tick, or Asian blue tick, is the vector of pathogenic microorganisms causing the deadly bovine babesiosis and anaplasmosis. The widespread resistance to acaricides in tick populations worldwide emphasizes that exploring novel targets for effective tick control is imperative. Fifty-three structural analogs of previously identified tick kinin antagonists were screened in a 'dual-addition' calcium fluorescence assay using a CHO-K1 cell line expressing the tick kinin receptor. Seven molecules were validated as non-cytotoxic antagonists, four of which were partial (SACC-0428764, SACC-0428780, SACC-0428800, and SACC-0428803), and three were full antagonists (SACC-0428799, SACC-0428801, and SACC-0428815). Four of these antagonists (SACC-0428764, SACC-0428780, SACC-0428799, and SACC-0428815) also inhibited the tick midgut contractions induced by the myotropic kinin agonist analog 1728, verifying their antagonistic bioactivity. The small molecules were tested on recombinant human neurokinin (NK) receptors, the one most similar to the invertebrate kinin receptors. Most molecules were inhibitors of the NK1 receptor, except SACC-0412066, a previously identified tick kinin receptor antagonist, which inhibited the NK1 receptor only at the highest concentration tested (25 μm). None of the molecules inhibited the NK3 human receptor. Molecules identified through this approach could be useful probes for studying the tick kinin signaling system and midgut physiology. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

DRUG PRECURSOR TARGETING THE BOMBESIN RECEPTOR FOR PEPTIDE-RECEPTOR RADIONUCLIDE THERAPY

Cancer is a leading cause of death worldwide. A promising modality for cancer treatment is peptide receptor radionuclide therapy. Therapeutic radionuclide is delivered using peptide-based vectors, which can bind to specific receptors on the cancer cell surface. Bombesin receptors are one of the receptors peculiar to many types of cancer, which can be targeted by peptide vectors. Peptides have a number of advantages, but they also have one serious drawback: low stability in the internal environment. To solve the problem, it is possible to the include a therapeutic peptide in the structure of a highly stable knottin peptide. Objective. The aim of the study is to examine the stability of BBN/C1-C2 structure, created on the basis of U5-scytotoxinSth1a knottin and bombesin tropic to bombesin receptor, and the ability of this structure to bind to target receptors on the cancer cell surface. Materials and Methods. BBN/C1-C2 peptide was obtained by solid-phase peptide synthesis. Then, is underwent chromatography purification under analytical chromatography and mass spectrometry control. Stability was studied by analytical chromatography. Competitive inhibition analysis was carried out using a fluorescently labeled GRP peptide with excess BBN/C1-C2 and fluorescently labeled BBN/C1-C2 with GRP bombesin receptor inhibitor. Cancer cell line PC-3 expressing bombesin receptors and normal cell line CHO-K1 not expressing bombesin receptors were used in the work. Results. The conducted studies have shown that hybrid BBN/C1-C2 peptide based on bombesin peptide inserted into the U5-scytotoxinSth1a knottin framework between the first and second cysteine residues has a greater stability compared to the commercial radiopharmaceutical PSMA-617. BBN/C1-C2 peptide is specific to bombesin receptor: it binds to PC-3 cancer cell line with a target bombesin receptor on its surface, and does not bind to the healthy CHO-K1 cell line, without a target receptor. BBN/C1-C2 peptide shows high affinity for the bombesin receptor, since GRP prevents its binding to the PC-3 cell line.

Anti-CD44 Variant 10 Monoclonal Antibody Exerts Antitumor Activity in Mouse Xenograft Models of Oral Squamous Cell Carcinomas.

CD44 regulates cell adhesion, proliferation, survival, and stemness and has been considered a tumor therapy target. CD44 possesses the shortest CD44 standard (CD44s) and a variety of CD44 variant (CD44v) isoforms. Since the expression of CD44v is restricted in epithelial cells and carcinomas compared to CD44s, CD44v has been considered a promising target for monoclonal antibody (mAb) therapy. We previously developed an anti-CD44v10 mAb, C44Mab-18 (IgM, kappa), to recognize the variant exon 10-encoded region. In the present study, a mouse IgG2a version of C44Mab-18 (C44Mab-18-mG2a) was generated to evaluate the antitumor activities against CD44-positive cells compared with the previously established anti-pan CD44 mAb, C44Mab-46-mG2a. C44Mab-18-mG2a exhibited higher reactivity compared with C44Mab-46-mG2a to CD44v3-10-overexpressed CHO-K1 (CHO/CD44v3-10) and oral squamous cell carcinoma cell lines (HSC-2 and SAS) in flow cytometry. C44Mab-18-mG2a exerted a superior antibody-dependent cellular cytotoxicity (ADCC) against CHO/CD44v3-10. In contrast, C44Mab-46-mG2a showed a superior complement-dependent cytotoxicity (CDC) against CHO/CD44v3-10. A similar tendency was observed in ADCC and CDC against HSC-2 and SAS. Furthermore, administering C44Mab-18-mG2a or C44Mab-46-mG2a significantly suppressed CHO/CD44v3-10, HSC-2, and SAS xenograft tumor growth compared with the control mouse IgG2a. These results indicate that C44Mab-18-mG2a could be a promising therapeutic regimen for CD44v10-positive tumors.

A genome-wide CRISPR/Cas9 screen identifies calreticulin as a selective repressor of ATF6α.

Activating transcription factor 6 (ATF6) is one of three endoplasmic reticulum (ER) transmembrane stress sensors that mediate the unfolded protein response (UPR). Despite its crucial role in long-term ER stress adaptation, regulation of ATF6 alpha (α) signalling remains poorly understood, possibly because its activation involves ER-to-Golgi and nuclear trafficking. Here, we generated an ATF6α/Inositol-requiring kinase 1 (IRE1) dual UPR reporter CHO-K1 cell line and performed an unbiased genome-wide CRISPR/Cas9 mutagenesis screen to systematically profile genetic factors that specifically contribute to ATF6α signalling in the presence and absence of ER stress. The screen identified both anticipated and new candidate genes that regulate ATF6α activation. Among these, calreticulin (CRT), a key ER luminal chaperone, selectively repressed ATF6α signalling: Cells lacking CRT constitutively activated a BiP::sfGFP ATF6α-dependent reporter, had higher BiP levels and an increased rate of trafficking and processing of ATF6α. Purified CRT interacted with the luminal domain of ATF6α in vitro and the two proteins co-immunoprecipitated from cell lysates. CRT depletion exposed a negative feedback loop implicating ATF6α in repressing IRE1 activity basally and overexpression of CRT reversed this repression. Our findings indicate that CRT, beyond its known role as a chaperone, also serves as an ER repressor of ATF6α to selectively regulate one arm of the UPR.

Recombinant Antibody-Producing Stable CHOK1 Pool Stability Study.

Mammalian cell line stability is an important consideration when establishing a biologics manufacturing process in the biopharmaceutical and in vitro diagnostics (IVD) industries. Traditional Chinese hamster ovary (CHO) cell line development methods use a random integration approach that requires transfection, selection, optional amplification, screenings, and single-cell cloning to select clones with acceptable productivity, product quality, and genetic stability. Site-specific integration reduces these disadvantages, and new technologies have been developed to mitigate risks associated with genetic instability. In this study, we applied the Leap-In® transposase-mediated expression system from ATUM to generate stable CHOK1 pools for the production of four recombinant antibody reagents for IVD immunoassays. CHO cell line stability is defined by consistent antibody production over time. Three of the CHOK1 pools maintained productivity suitable for manufacturing, with high antibody yields. The productivity of the remaining CHOK1 pool decreased over time; however, derivative clones showed acceptable stability. l-glutamine had variable effects on CHOK1 cell line or stable pool stability and significantly affected antibody product titer. Compared with traditional random integration methods, the ATUM Leap-In system can reduce the time needed to develop new immunoassays by using semi site-specific integration to generate high-yield stable pools that meet manufacturing stability requirements.

Effects of buffer composition and plasmid toxicity on electroporation-based non-viral gene delivery in mammalian cells using bursts of nanosecond and microsecond pulses.

Gene electrotransfer (GET) is non-viral gene delivery technique, also known as electroporation-mediated gene delivery or electrotransfection. GET is a method used to introduce foreign genetic material (such as DNA or RNA) into cells by applying external pulsed electric fields (PEFs) to create temporary pores in the cell membrane. This study was undertaken to examine the impact of buffer composition on the efficiency of GET in mammalian cells Also, we specifically compared the effectiveness of high-frequency nanosecond (ns) pulses with standard microsecond (µs) pulses. For the assessment of cell transfection efficiency and viability, flow cytometric analysis, luminescent assays, and measurements of metabolic activity were conducted. The efficiency of electrotransfection was evaluated using two different proteins encoding plasmids (pEGFP-N1 and Luciferase-pcDNA3). The investigation revealed that the composition of the electroporation buffer significantly influences the efficacy of GET in CHO-K1 cell line. The different susceptibility of cell lines to the electric field and the plasmid cytotoxicity were reported. It was also shown that electroporation with nanosecond duration PEF protocols ensured equivalent or even better transfection efficiency than standard µsPEF. Additionally, we successfully performed long-term transfection of the murine 4T1 cell line using high-frequency nanosecond PEFs and confirmed its' applicability in an in vivo model. The findings from the study can be applied to optimize electrotransfection conditions.

Efficient generation of a stable CHO-K1 cell line overexpressing the human water channel aquaporin-5 as tool to generate therapeutic antibodies

Aquaporins (AQPs) are a family of water permeable channels expressed on the plasma membrane with AQP5 being the major channel expressed in several human tissues including salivary and lacrimal glands. Anti-AQP5 autoantibodies have been observed in patients with Sjögren’s syndrome who are characterised by dryness of both salivary and lacrimal glands, and they have been implicated in the underlying mechanisms of glandular dysfunction. AQP5 is formed by six transmembrane helices linked with three extracellular and two intracellular loops. Develop antibodies against membrane protein extracellular loops can be a challenge due to the difficulty in maintaining these proteins as recombinant in their native form. Therefore, in this work we aimed to generate an efficient stable-transfected cell line overexpressing human AQP5 (CHO-K1/AQP5) to perform primarily cell-based phage display biopanning experiments to develop new potential recombinant antibodies targeting AQP5. We also showed that the new CHO-K1/AQP5 cell line can be used to study molecular mechanisms of AQP5 sub-cellular trafficking making these cells a useful tool for functional studies.

Antibacterial Efficacy and Mechanisms of Action of a Novel Beta-Defensin from Snakehead Murrel, Channa striata.

Beta-defensins, identified from fishes, constitute a crucial category of antimicrobial peptides important in combating bacterial fish pathogens. The present investigation centers on the molecular and functional characterization of CsDef, a 63-amino acid beta-defensin antimicrobial peptide derived from snakehead murrel (Channa striata). The physicochemical attributes of CsDef align with the distinctive characteristics observed in AMPs. CsDef was recombinantly produced, and the recombinant peptide, rCsDef, exhibited notable antibacterial efficacy against bacterial fish pathogens with an MIC of 16μM for V. proteolyticus. A. hydrophila exhibited 91% inhibition, E. tarda 92%, and V. harveyi 53% at 32μM of rCsDef. The rCsDef exhibited a multifaceted mechanism of action against bacteria, i.e., through membrane depolarization, membrane permeabilization, and generation of ROS. The rCsDef was non-hemolytic to hRBCs and non-cytotoxic to normal mammalian cell line CHO-K1. However, it exhibited anticancer properties in MCF-7. rCsDef demonstrated notable stability with respect to pH, temperature, salt, metal ions, and proteases. These findings suggest it is a potential candidate molecule for prospective applications in aquaculture.

Super7 passaging method to improve Chinese hamster ovary cell fed-batch performance.

Chinese hamster ovary (CHO) cells are widely used to manufacture biopharmaceuticals, most of all monoclonal antibodies (mAbs). Some CHO cell lines exhibit production instability, where the productivity of the cells decreases as a function of time in culture. To counter this, we designed a passaging strategy that, rather than maximizing the time spent in log-growth phase, mimics the first 7 days of a fed-batch production process. Cultures passaged using this method had lower net growth rates and were more oxidative throughout 6 weeks of passaging. Fed-batch cultures inoculated by cells passaged using this method had increased net growth rates, oxidative metabolism, and volumetric productivity compared to cells passaged using a conventional strategy. Cells from unstable cell lines passaged by this new method produced 80%-160% more mAbs per unit volume than cells passaged by a conventional method. This new method, named Super7, provides the ability to mitigate the impact of production instability in CHO-K1 cell lines without a need for further cell line creation, genetic engineering, or medium development.

Accelerated generation of gene-engineered monoclonal CHO cell lines using FluidFM nanoinjection and CRISPR/Cas9.

Chinese hamster ovary (CHO) cells are the commonly used mammalian host system to manufacture recombinant proteins including monoclonal antibodies. However unfavorable non-human glycoprofile displayed on CHO-produced monoclonal antibodies have negative impacts on product quality, pharmacokinetics, and therapeutic efficiency. Glycoengineering such as genetic elimination of genes involved in glycosylation pathway in CHO cells is a viable solution but constrained due to longer timeline and laborious workflow. Here, in this proof-of-concept (PoC) study, we present a novel approach coined CellEDIT to engineer CHO cells by intranuclear delivery of the CRISPR components to single cells using the FluidFM technology. Co-injection of CRISPR system targeting BAX, DHFR, and FUT8 directly into the nucleus of single cells, enabled us to generate triple knockout CHO-K1 cell lines within a short time frame. The proposed technique assures the origin of monoclonality without the requirement of limiting dilution, cell sorting or positive selection. Furthermore, the approach is compatible to develop both single and multiple knockout clones (FUT8, BAX, and DHFR) in CHO cells. Further analyses on single and multiple knockout clones confirmed the targeted genetic disruption and altered protein expression. The knockout CHO-K1 clones showed the persistence of gene editing during the subsequent passages, compatible with serum free chemically defined media and showed equivalent transgene expression like parental clone.

Effects of process intensification on homogeneity of an IgG1:κ monoclonal antibody during perfusion culture

The pharmaceutical industry employs various strategies to improve cell productivity. These strategies include process intensification, culture media improvement, clonal selection, media supplementation and genetic engineering of cells. However, improved cell productivity has inherent risk of impacting product quality attributes (PQA). PQAs may affect the products’ efficacy via stability, bioavailability, or in vivo bioactivity. Variations in manufacturing process may introduce heterogeneity in the products by altering the type and extent of N-glycosylation, which is a PQA of therapeutic proteins. We investigated the effect of different cell densities representing increasing process intensification in a perfusion cell culture on the production of an IgG1-κ monoclonal antibody from a CHO-K1 cell line. This antibody is glycosylated both on light chain and heavy chain. Our results showed that the contents of glycosylation of IgG1-κ mAb increased in G0F and fucosylated type glycans as a group, whereas sialylated type glycans decreased, for the mAb whole protein. Overall, significant differences were observed in amounts of G0F, G1F, G0, G2FS1, and G2FS2 type glycans across all process intensification levels. G2FS2 and G2 type N-glycans were predominantly quantifiable from light chain rather than heavy chain. It may be concluded that there is a potential impact to product quality attributes of therapeutic proteins during process intensification via perfusion cell culture that needs to be assessed. Since during perfusion cell culture the product is collected throughout the duration of the process, lot allocation needs careful attention to process parameters, as PQAs are affected by the critical process parameters (CPPs).Key points• Molecular integrity may suffer with increasing process intensity.• Galactosylated and sialylated N-glycans may decrease.• Perfusion culture appears to maintain protein charge structure.

Comprehensive Comparison of Baculoviral and Plasmid Gene Delivery in Mammalian Cells.

(1) Recombinant protein production in mammalian cells is either based on transient transfection processes, often inefficient and underlying high batch-to-batch variability, or on laborious generation of stable cell lines. Alternatively, BacMam, a transduction process using the baculovirus, can be employed. (2) Six transfecting agents were compared to baculovirus transduction in terms of transient and stable protein expression characteristics of the model protein ACE2-eGFP using HEK293-6E, CHO-K1, and Vero cell lines. Furthermore, process optimization such as expression enhancement using sodium butyrate and TSA or baculovirus purification was assessed. (3) Baculovirus transduction efficiency was superior to all transfection agents for all cell lines. Transduced protein expression was moderate, but an 18-fold expression increase was achieved using the enhancer sodium butyrate. Ultracentrifugation of baculovirus from a 3.5 L bioreactor significantly improved the transduction efficiency and protein expression. Stable cell lines were obtained with each baculovirus transduction, yet stable cell line generation after transfection was highly unreliable. (4) This study demonstrated the superiority of the BacMam platform to standard transfections. The baculovirus efficiently transduced an array of cell lines both transiently and stably and achieved the highest efficiency for all tested cell lines. The feasibility of the scale-up of baculovirus production was demonstrated and the possibility of baculovirus purification was successfully explored.

Везикулы типичных и геновариантов штаммов холерных вибрионов О1 Эль Тор, их выделение и характеристика

was found that a typical strain and genovariants of Vibrio cholerae O1 when cultured in AKI medium at different growth stages release outer membrane vesicles into the environment. Preparations of vesicles were obtained by ammonium sulfate precipitation and visualized by electron microscopy. Using monoclonal antibodies and polyclonal antitoxic conjugate, the presence of lipopolysaccharide and outer membrane proteins OmpU and OmpT, as well as cholera toxin in these structures was determined. On the model of cell culture of two cell lines CHO-K1 and HuTu 80 it was shown that in the presence of vesicles morphological changes of target cells characteristic for cholera toxin are observed. The results obtained suggest that the content of outer membrane vesicles depends on the stage of vibrio growth, and the biologically active substances produced by them are capable of causing cell damage, thereby provoking an inflammatory reaction of cells in the host organism.

Identification of a New Integration Site and Study on Site-Specific Integration in CHO-K1 Cells.

Site-specific integration is an important approach used to address the problem of unstable cell lines in industry. In this study, we observed a reduction in the gene copy number and antibody production in a CHOK1 cell line BA03 capable of high antibody expression. We identified a new integration site named locus 7 in the intron region of the parva gene through sequencing, FISH, and genome walking. We demonstrate that the integration of the exogenous gene at this locus does not affect the transcription of the parva and, therefore, has a minimal impact on cell growth. We designed sgRNA and donor vectors to integrate the etanercept-coding gene into locus 7 and obtained a cell line, SSI-4. We performed a passaged stability study on SSI-4 and proved the possibility of the stable, site-specific integration of exogenous genes at this locus in terms of integration site, copy number, expression level, and cell growth. In summary, our study has identified a new integration site suitable for site-specific integration, which lays the foundation for the subsequent development of site-specific integration cell lines.

Production and Study of Immunochemical Properties of Stabilized Env Trimer of Recombinant Form CRF63_02A6 of HIV-1.

Stabilized trimers of the HIV-1 envelope glycoprotein Env are capable of inducing a potent and sustained broadly neutralizing antibody response in laboratory animals and therefore are attractive targets for anti-HIV vaccine development. In this work, a stable producer of the trimer Env recombinant form CRF63_02A6 of HIV-1 was derived from the CHO-K1 cell line. Using immunochemical assays, the trimers synthesized in CHO-K1 cells were shown to be recognized by both monoclonal broadly neutralizing antibodies and sera from HIV-positive patients. The resulting trimers of the recombinant form CRF63_02A6 of HIV-1 can be used both for structural studies and as a candidate vaccine immunogen against HIV-1.

Anti-CD19/CD8 bispecific T cell engager for the potential treatment of B cell malignancies

The administration of blinatumomab was accompanied by several adverse effects, including activation of regulatory T-cells and cytokine storm. The objective of this study was to produce and evaluate a novel αCD8/CD19 BiTE (αCD8/CD19) with the potency to directly target CD8+T-cells. In-silico studies were utilized for determining proper folding, receptor binding, and structural stability of αCD8/CD19 protein. Western blotting and indirect surface staining were used to evaluate the size accuracy and binding potency of the purified protein. Functionality was assessed for granzyme B production, cytotoxicity, and proliferation. TheαCD8/CD19recombinant protein was produced in the CHO-K1 cell line with a final concentration of 1.94 mg/l. The αCD8/CD19 bound to CD8+and CD19+cell lines and induced significant granzyme B production, cytotoxic activity and proliferation potential in the presence of IL-2 and tumor target cells. The maximum CD8+T-cell biological activity was observed on the 10th day with 10:1 effector-to-target ratio.

Recombinant Porcine Interferon-α Decreases Pseudorabies Virus Infection.

Interferon (IFN) is a cell-secreted cytokine possessing biological activities including antiviral functioning, immune regulation, and others. Interferon-alpha (IFN-α) mainly derives from plasmacytoid dendritic cells, which activate natural killer cells and regulate immune responses. IFN-α responds to the primary antiviral mechanism in the innate immune system, which can effectively cure acute infectious diseases. Pseudorabies (PR) is an acute infectious disease caused by pseudorabies virus (PRV). The clinical symptoms of PRV are as follows: reproductive dysfunction among pregnant sows and high mortality rates among piglets. These pose a severe threat to the swine industry. Related studies show that IFN-α has broad applications in preventing and treating viral diseases. Therefore, a PRV mouse model using artificial infection was established in this study to explore the pathogenic effect of IFN-α on PRV. We designed a sequence with IFN-α4 (M28623, Genbank) and cloned it on the lentiviral vector. CHO-K1 cells were infected and identified using WB and RT-PCR; a CHO-K1 cell line with a stable expression of the recombinant protein PoIFN-α was successfully constructed. H&E staining and virus titer detection were used to investigate the recombinant protein PoIFN-α's effect on PR in BALB/c mice. The results show that the PoIFN-α has a preventive and therapeutic impact on PR. In conclusion, the recombinant protein can alleviate symptoms and reduce the replication of PRV in vivo.