| 51. |
- McGinn, Steven, et al.
(författare)
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New Technologies for DNA analysis-A review of the READNA Project.
- 2016
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Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784.
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Forskningsöversikt (refereegranskat)abstract
- The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received funding from the European Commission for 4 1/2 years. The objectives of the project revolved around technological developments in nucleic acid analysis. The project partners have discovered, created and developed a huge body of insights into nucleic acid analysis, ranging from improvements and implementation of current technologies to the most promising sequencing technologies that constitute a 3(rd) and 4(th) generation of sequencing methods with nanopores and in situ sequencing, respectively.
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| 52. |
- Mebrahtu, Aman, et al.
(författare)
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Co-culture platform for tuning of cancer receptor density allows for evaluation of bispecific immune cell engagers
- 2024
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 79, s. 120-126
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Tidskriftsartikel (refereegranskat)abstract
- Cancer immunotherapy, where a patient's immune system is harnessed to eradicate cancer cells selectively, is a leading strategy for cancer treatment. However, successes with immune checkpoint inhibitors (ICI) are hampered by reported systemic and organ-specific toxicities and by two-thirds of the patients being non-responders or subsequently acquiring resistance to approved ICIs. Hence substantial efforts are invested in discovering novel targeted immunotherapies aimed at reduced side-effects and improved potency. One way is utilizing the dual targeting feature of bispecific antibodies, which have made them increasingly popular for cancer immunotherapy. Easy and predictive screening methods for activation ranking of candidate drugs in tumor contra non-tumor environments are however lacking. Herein, we present a cell-based assay mimicking the tumor microenvironment by co-culturing B cells with engineered human embryonic kidney 293 T cells (HEK293T), presenting a controllable density of platelet-derived growth factor receptor β (PDGFRβ). A target density panel with three different surface protein levels on HEK293T cells was established by genetic constructs carrying regulatory elements limiting RNA translation of PDGFRβ. We employed a bispecific antibody-affibody construct called an AffiMab capable of binding PDGFRβ on cancer cells and CD40 expressed by B cells as a model. Specific activation of CD40-mediated signaling of immune cells was demonstrated with the two highest receptor-expressing cell lines, Level 2/3 and Level 4, while low-to-none in the low-expressing cell lines. The concept of receptor tuning and the presented co-culture protocol may be of general utility for assessing and developing novel bi-specific antibodies for immuno-oncology applications.
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| 53. |
- Mersmann, Michael, et al.
(författare)
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Towards proteome scale antibody selections using phage display
- 2010
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Ingår i: NEW BIOTECHNOL. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 27:2, s. 118-128
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Tidskriftsartikel (refereegranskat)abstract
- In vitro antibody generation by panning a large universal gene library with phage display was employed to generate antibodies to more than 60 different antigens. Of particular interest was a comparison of pannings on 20 different SH2 domains provided by the Structural Genomics Consortium (SGC). Streamlined methods for high throughput antibody generation developed within the 'Antibody Factory' of the German National Genome Research Network (NGFN) were demonstrated to minimise effort and provide a reliable and robust source for antibodies. For the SH2 domains, in two successive series of selections, 2668 clones were analysed, resulting in 347 primary hits in ELISA. Half of these hits were further analysed, and more than 90 different scFv antibodies to all antigens were identified. The validation of selected antibodies by cross-reactivity ELISA, western blot and on protein microarrays demonstrated the versatility of the in vitro antibody selection pipeline to generate a renewable resource of highly specific monoclonal binders in proteome scale numbers with substantially reduced effort and time.
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| 54. |
- Mestre Borras, Anna, 1994-, et al.
(författare)
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Generation of an anti-idiotypic affibody-based masking domain for conditional activation of EGFR-targeting
- 2023
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 73, s. 9-18
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Tidskriftsartikel (refereegranskat)abstract
- Conditional activation of engineered affinity proteins by proteolytic processing is an interesting approach for a wide range of applications. We have generated an anti-idiotypic masking domain with specificity for the binding surface of an EGFR-targeting affibody molecule using an in-house developed staphylococcal display method. The masking domain could specifically abrogate EGFR-binding on cancer cells when fused to the EGFR-targeting affibody molecule via a linker comprising a protease cleavage site. EGFR-binding was restored by proteolytic cleavage of the linker region resulting in release of the masking domain. A saturation mutagenesis study provided detailed information on the interaction between the EGFR-targeting affibody molecule and the masking domain. Introducing an anti-idiotypic masking affibody domain is a viable approach for blocking EGFR-binding and al-lows for conditional activation by proteolytic processing. The results warrant further studies evaluating the therapeutic and diagnostic applicability both in vitro and in vivo.
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| 55. |
- Mezger, Anja, et al.
(författare)
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Highly specific DNA detection employing ligation on suspension bead array readout
- 2015
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 32:5, s. 504-510
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Tidskriftsartikel (refereegranskat)abstract
- We show for the first time that monomerized rolling circle amplification (RCA) products can be directly detected with the Luminex suspension bead array readout without the need of PCR amplification. Furthermore, using monomerized RCA products to guide ligation of the detection oligonucleotide (DO) to barcode sequences on the magnetic Luminex beads, combined with efficient washing and increased measurement temperature, yields a higher signal to noise ratio. As a proof-of-principle, we demonstrate detection of pathogenic DNA sequences with high reproducibility, sensitivity and a dynamic range over four orders of magnitude. Using padlock probes in combination with bead suspension arrays opens up the possibility for highly multiplexed DNA targeting and readout.
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| 56. |
- Moradi, Mona, et al.
(författare)
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Autophagy and intracellular product degradation genes identified by systems biology analysis reduce aggregation of bispecific antibody in CHO cells
- 2022
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 68, s. 68-76
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Tidskriftsartikel (refereegranskat)abstract
- Aggregation of therapeutic bispecific antibodies negatively affects the yield, shelf-life, efficacy and safety of these products. Pairs of stable Chinese hamster ovary (CHO) cell lines produced two difficult-to-express bispecific antibodies with different levels of aggregated product (10-75% aggregate) in a miniaturised bioreactor system. Here, transcriptome analysis was used to interpret the biological causes for the aggregation and to identify strategies to improve product yield and quality. Differential expression-and gene set analysis revealed upregulated proteasomal degradation, unfolded protein response and autophagy processes to be correlated with reduced protein aggregation. Fourteen candidate genes with the potential to reduce aggregation were co expressed in the stable clones for validation. Of these, HSP90B1, DDIT3, AKT1S1, and ATG16L1, were found to significantly lower aggregation in the stable producers and two (HSP90B1 and DNAJC3) increased titres of the anti-HER2 monoclonal antibody trastuzumab by 50% during transient expression. It is suggested that this approach could be of general use for defining aggregation bottlenecks in CHO cells.
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| 57. |
- Moukouli, Maria, et al.
(författare)
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Cloning and optimized expression of a GH-11 xylanase from Fusarium oxysporum in Pichia pastoris
- 2011
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 28:4, s. 369-374
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Tidskriftsartikel (refereegranskat)abstract
- The endo-1,4-beta-xylanase gene xyn11a from Fusarium oxysporum, member of the fungal glycosyl hydrolase (GH) family 11, was cloned and expressed in Pichia pastoris. The mature xylanase gene, which generates after the excision of one intron and the secreting signal peptide, was placed under the control of an alcohol oxidase promoter (AOX1) in the plasmid pPICZ alpha C. The final construction was integrated into the genome of the methylotrophic yeast P. pastoris X33 and the ability to produce xylanase activity was evaluated in flask cultures. Recombinant P. pastoris efficiently secreted xylanase into the medium and produced high level of enzymatic activity (110 U/ml) after 216 hours of growth, under methanol induction. To achieve higher enzyme production, the influence of initial pH, methanol concentration, agitation and flask design was evaluated. Under optimum culture conditions, production of the recombinant xylanase increased by 50%, reaching a final yield of 170 U/ml, underpinning aeration as the most important factor in improving enzyme production.
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| 58. |
- Mravinacová, Sára, et al.
(författare)
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A cell-free high throughput assay for assessment of SARS-CoV-2 neutralizing antibodies
- 2022
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 66, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- Highly accurate serological tests are key to assessing the prevalence of SARS-CoV-2 antibodies and the level of immunity in the population. This is important to predict the current and future status of the pandemic. With the recent emergence of new and more infectious SARS-CoV-2 variants, assays allowing for high throughput analysis of antibodies able to neutralize SARS-CoV-2 become even more important. Here, we report the development and validation of a robust, high throughput method, which enables the assessment of antibodies inhibiting the binding between the SARS-CoV-2 spike protein and angiotensin converting enzyme 2 (ACE2). The assay uses recombinantly produced spike-f and ACE2 and is performed in a bead array format, which allows analysis of up to 384 samples in parallel per instrument over seven hours, demanding only one hour of manual handling. The method is compared to a microneutralization assay utilising live SARS-CoV-2 and is shown to deliver highly correlating data. Further, a comparison with a serological method that measures all antibodies recognizing the spike protein shows that this type of assessment provides important insights into the neutralizing efficiency of the antibodies, especially for individuals with low antibody levels. This method can be an important and valuable tool for large-scale assessment of antibody-based neutralization, including neutralization of new spike variants that might emerge.
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| 59. |
- Napoleone, Antonino, et al.
(författare)
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Fed-batch production assessment of a tetravalent bispecific antibody : A case study on piggyBac stably transfected HEK293 cells
- 2021
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 65, s. 9-19
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Tidskriftsartikel (refereegranskat)abstract
- The transition from preclinical biological drug development into clinical trials requires an efficient upscaling process. In this context, bispecific antibody drugs are particularly challenging due to their propensity to form aggregates and generally produce low titers. Here, the upscaling process for a tetravalent bispecific antibody expressed by a piggyBac transposon-mediated stable HEK293 cell pool has been evaluated. The project was performed as a case study at Testa Center, a non-GMP facility for scale-up testing of biologics in Sweden, and encompassed media adaptation strategies, fed-batch optimization and a novel antibody purification technology. The cell pool was adapted to different culture media for evaluation in terms of cell viability and titers compared to its original Expi293 Expression Medium. These parameters were assessed in both sequential stepwise adaption and direct media exchanges. By this, a more affordable medium was identified that did not require stepwise adaptation and with similar titers and viability as in the Expi293 Expression Medium. Fed-batch optimizations resulted in culture densities reaching up to 20 x 106 viable cells/mL with over 90 % viability 12 days postinoculum, and antibody titers three times higher than corresponding batch cultures. By implementing a novel high-speed protein A fiber technology (Fibro PrismA) with a capture residence time of only 7.5 s, 8 L of supernatant could be purified in 4.5 h without compromising the purity, structural integrity and function of the bispecific antibody. Results from this study related to medium adaptation and design of fed-batch protocols will be highly beneficial during the forthcoming scale-up of this therapeutic antibody.
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| 60. |
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