@article{YeKeicherGentschevetal.2021,
  author    = {Ye, Mingyu and Keicher, Markus and Gentschev, Ivaylo and Szalay, Aladar A.},
  title     = {Efficient selection of recombinant fluorescent vaccinia virus strains and rapid virus titer determination by using a multi-well plate imaging system},
  series = {Biomedicines},
  volume    = {9},
  journal   = {Biomedicines},
  number    = {8},
  issn      = {2227-9059},
  doi       = {10.3390/biomedicines9081032},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245104},
  year      = {2021},
  abstract  = {Engineered vaccinia virus (VACV) strains are used extensively as vectors for the development of novel cancer vaccines and cancer therapeutics. In this study, we describe for the first time a high-throughput approach for both fluorescent rVACV generation and rapid viral titer measurement with the multi-well plate imaging system, IncuCyte\(^®\)S3. The isolation of a single, well-defined plaque is critical for the generation of novel recombinant vaccinia virus (rVACV) strains. Unfortunately, current methods of rVACV engineering via plaque isolation are time-consuming and laborious. Here, we present a modified fluorescent viral plaque screening and selection strategy that allows one to generally obtain novel fluorescent rVACV strains in six days, with a minimum of just four days. The standard plaque assay requires chemicals for fixing and staining cells. Manual plaque counting based on visual inspection of the cell culture plates is time-consuming. Here, we developed a fluorescence-based plaque assay for quantifying the vaccinia virus that does not require a cell staining step. This approach is less toxic to researchers and is reproducible; it is thus an improvement over the traditional assay. Lastly, plaque counting by virtue of a fluorescence-based image is very convenient, as it can be performed directly on the computer.},
  language  = {en}
}
@article{GentschevMuellerAdelfingeretal.2011,
  author    = {Gentschev, Ivaylo and M{\"u}ller, Meike and Adelfinger, Marion and Weibel, Stephanie and Grummt, Friedrich and Zimmermann, Martina and Bitzer, Michael and Heisig, Martin and Zhang, Qian and Yu, Yong A. and Chen, Nanhai G. and Stritzker, Jochen and Lauer, Ulrich M. and Szalay, Aladar A.},
  title     = {Efficient Colonization and Therapy of Human Hepatocellular Carcinoma (HCC) Using the Oncolytic Vaccinia Virus Strain GLV-1h68},
  series = {PLOS ONE},
  volume    = {6},
  journal   = {PLOS ONE},
  number    = {7},
  doi       = {10.1371/journal.pone.0022069},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135319},
  pages     = {e22069},
  year      = {2011},
  abstract  = {Virotherapy using oncolytic vaccinia virus strains is one of the most promising new strategies for cancer therapy. In this study, we analyzed for the first time the therapeutic efficacy of the oncolytic vaccinia virus GLV-1h68 in two human hepatocellular carcinoma cell lines HuH7 and PLC/PRF/5 (PLC) in cell culture and in tumor xenograft models. By viral proliferation assays and cell survival tests, we demonstrated that GLV-1h68 efficiently colonized, replicated in, and did lyse these cancer cells in culture. Experiments with HuH7 and PLC xenografts have revealed that a single intravenous injection (i.v.) of mice with GLV-1h68 resulted in a significant reduction of primary tumor sizes compared to uninjected controls. In addition, replication of GLV-1h68 in tumor cells led to strong inflammatory and oncolytic effects resulting in intense infiltration of MHC class II-positive cells like neutrophils, macrophages, B cells and dendritic cells and in up-regulation of 13 pro-inflammatory cytokines. Furthermore, GLV-1h68 infection of PLC tumors inhibited the formation of hemorrhagic structures which occur naturally in PLC tumors. Interestingly, we found a strongly reduced vascular density in infected PLC tumors only, but not in the non-hemorrhagic HuH7 tumor model. These data demonstrate that the GLV-1h68 vaccinia virus may have an enormous potential for treatment of human hepatocellular carcinoma in man.},
  language  = {en}
}
@article{PetrovGentschevVyalkovaetal.2020,
  author    = {Petrov, Ivan and Gentschev, Ivaylo and Vyalkova, Anna and Elashry, Mohamed I. and Klymiuk, Michele C. and Arnhold, Stefan and Szalay, Aladar A.},
  title     = {Canine Adipose-Derived Mesenchymal Stem Cells (cAdMSCs) as a "Trojan Horse" in Vaccinia Virus Mediated Oncolytic Therapy against Canine Soft Tissue Sarcomas},
  series = {Viruses},
  volume    = {12},
  journal   = {Viruses},
  number    = {7},
  doi       = {10.3390/v12070750},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236007},
  year      = {2020},
  abstract  = {Several oncolytic viruses (OVs) including various human and canine adenoviruses, canine distemper virus, herpes-simplex virus, reovirus, and members of the poxvirus family, such as vaccinia virus and myxoma virus, have been successfully tested for canine cancer therapy in preclinical and clinical settings. The success of the cancer virotherapy is dependent on the ability of oncolytic viruses to overcome the attacks of the host immune system, to preferentially infect and lyse cancer cells, and to initiate tumor-specific immunity. To date, several different strategies have been developed to overcome the antiviral host defense barriers. In our study, we used canine adipose-derived mesenchymal stem cells (cAdMSCs) as a "Trojan horse" for the delivery of oncolytic vaccinia virus Copenhagen strain to achieve maximum oncolysis against canine soft tissue sarcoma (CSTS) tumors. A single systemic administration of vaccinia virus-loaded cAdMSCs was found to be safe and led to the significant reduction and substantial inhibition of tumor growth in a CSTS xenograft mouse model. This is the first example that vaccinia virus-loaded cAdMSCs could serve as a therapeutic agent against CSTS tumors.},
  language  = {en}
}
@article{HessStritzkerHaertletal.2011,
  author    = {Hess, Michael and Stritzker, Jochen and H{\"a}rtl, Barbara and Sturm, Julia and Gentschev, Ivaylo and Szalay, Aladar},
  title     = {Bacterial glucuronidase as general marker for oncolytic virotherapy or other biological therapies},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69163},
  year      = {2011},
  abstract  = {Background: Oncolytic viral tumor therapy is an emerging field in the fight against cancer with rising numbers of clinical trials and the first clinically approved product (Adenovirus for the treatment of Head and Neck Cancer in China) in this field. Yet, until recently no general (bio)marker or reporter gene was described that could be used to evaluate successful tumor colonization and/or transgene expression in other biological therapies. Methods: Here, a bacterial glucuronidase (GusA) encoded by biological therapeutics (e.g. oncolytic viruses) was used as reporter system. Results: Using fluorogenic probes that were specifically activated by glucuronidase we could show 1) preferential activation in tumors, 2) rena l excretion of the activated fluorescent compounds and 3) reproducible detection of GusA in the serum of oncolytic vaccinia virus treated, tumor bearing mice in several tumor models. Time course studies revealed that reliable differentiation between tumor bearing and healthy mice can be done as early as 9 days post injection of the virus. Regarding the sensitivity of the newly developed assay system, we could show that a single infected tumor cell could be reliably detected in this assay. Conclusion: GusA therefore has the potential to be used as a general marker in the preclinical and clinical evaluation of (novel) biological therapies as well as being useful for the detection of rare cells such as circulating tumor cells},
  subject      = {Virologie},
  language  = {en}
}
@article{YeWilhelmGentschevetal.2021,
  author    = {Ye, Mingyu and Wilhelm, Martina and Gentschev, Ivaylo and Szalay, Alad{\´a}r},
  title     = {A modified limiting dilution method for monoclonal stable cell line selection using a real-time fluorescence imaging system: A practical workflow and advanced applications},
  series = {Methods and Protocols},
  volume    = {4},
  journal   = {Methods and Protocols},
  number    = {1},
  doi       = {10.3390/mps4010016},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228896},
  year      = {2021},
  abstract  = {Stable cell lines are widely used in laboratory research and pharmaceutical industry. They are mainly applied in recombinant protein and antibody productions, gene function studies, drug screens, toxicity assessments, and for cancer therapy investigation. There are two types of cell lines, polyclonal and monoclonal origin, that differ regarding their homogeneity and heterogeneity. Generating a high-quality stable cell line, which can grow continuously and carry a stable genetic modification without alteration is very important for most studies, because polyclonal cell lines of multicellular origin can be highly variable and unstable and lead to inconclusive experimental results. The most commonly used technologies of single cell originate monoclonal stable cell isolation in laboratory are fluorescence-activated cell sorting (FACS) sorting and limiting dilution cloning. Here, we describe a modified limiting dilution method of monoclonal stable cell line selection using the real-time fluorescence imaging system IncuCyte\(^®\)S3.},
  language  = {en}
}