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2.
Biotechnol Bioeng ; 114(3): 701-704, 2017 03.
Article in English | MEDLINE | ID: mdl-27617904

ABSTRACT

Recombinant CHO (Chinese hamster ovary) cell lines producing therapeutic proteins often lose their production capability during long-term cultivation. To ensure that CHO production cell lines can be up-scaled to high-volume bioreactors, labor intensive stability studies of several months have to be performed to deselect clones that are losing productivity over time. The ability to predict whether clones will produce recombinant proteins at constant high levels, for example, through determination of biomarkers such as expression of specific genes, plasmid integration sites, or epigenetic patterns, or even to improve CHO host cell lines to increase the probability of the generation of stable clones would be highly beneficial. Previously, we reported that the lack of a telomeric region of chromosome 8 correlates with increased productivities and higher production stabilities of monoclonal antibody expressing CHO cell lines (Ritter A, Voedisch B, Wienberg J, Wilms B, Geisse S, Jostock T, Laux H. 2016a. Biotechnol Bioeng 113(5):1084-1093). Herein, we describe that the knock-out of the gene Fam60A, which is one of the genes located within the telomeric region of chromosome 8, in CHO-K1a cells leads to the isolation of significantly more clones with higher protein production stabilities of monoclonal antibodies during long-term cultivation. Biotechnol. Bioeng. 2017;114: 701-704. © 2016 Wiley Periodicals, Inc.


Subject(s)
Cell Engineering/methods , DNA-Binding Proteins/physiology , Recombinant Proteins/metabolism , Acetylation , Animals , Bioreactors , CHO Cells , Cricetinae , Cricetulus , DNA-Binding Proteins/genetics , Gene Knockout Techniques , Histones , Recombinant Proteins/analysis , Recombinant Proteins/chemistry , Recombinant Proteins/genetics
3.
Biotechnol Bioeng ; 112(12): 2505-15, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26058896

ABSTRACT

Human cytomegalovirus (HCMV) causes significant disease worldwide. Multiple HCMV vaccines have been tested in man but only partial protection has been achieved. The HCMV gH/gL/UL128/UL130/UL131A complex (Pentamer) is the main target of neutralizing antibodies in HCMV seropositive individuals and raises high titers of neutralizing antibodies in small animals and non-human primates (NHP). Thus, Pentamer is a promising candidate for an effective HCMV vaccine. Development of a Pentamer-based subunit vaccine requires expression of high amounts of a functional and stable complex. We describe here the development of a mammalian expression system for large scale Pentamer production. Several approaches comprising three different CHO-originated cell lines and multiple vector as well as selection strategies were tested. Stable cell pools expressed the HCMV Pentamer at a titer of approximately 60 mg/L at laboratory scale. A FACS-based single cell sorting approach allowed selection of a highly expressing clone producing Pentamer at the level of approximately 400 mg/L in a laboratory scale fed-batch culture. Expression in a 50 L bioreactor led to the production of HCMV Pentamer at comparable titers indicating the feasibility of further scale-up for manufacturing at commercial scale. The CHO-produced HCMV Pentamer bound to a panel of human neutralizing antibodies and raised potently neutralizing immune response in mice. Thus, we have generated an expression system for the large scale production of functional HCMV Pentamer at high titers suitable for future subunit vaccine production.


Subject(s)
CHO Cells , Cytomegalovirus Vaccines/immunology , Gene Expression , Viral Proteins/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Cricetulus , Cytomegalovirus/genetics , Cytomegalovirus Vaccines/administration & dosage , Cytomegalovirus Vaccines/genetics , Cytomegalovirus Vaccines/metabolism , Mice , Protein Multimerization , Vaccines, Subunit/administration & dosage , Vaccines, Subunit/genetics , Vaccines, Subunit/immunology , Vaccines, Subunit/metabolism , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Vaccines, Synthetic/metabolism , Viral Proteins/genetics , Viral Proteins/metabolism
4.
Z Arztl Fortbild Qualitatssich ; 100(4): 243-52, 2006.
Article in German | MEDLINE | ID: mdl-16878793

ABSTRACT

BACKGROUND: Legislation, professional medical societies and health care providers urge neurological departments to increase focus on more effective structures and processes. This, however, depends on the appreciation of quality features by the physicians involved. GOAL: The present study aimed to identify neurologists' subjective quality criteria, the analysis of influential factors, and a comparison with existing guidelines. METHOD: In a multicentre survey, 99 registrars and senior registrars from 30 clinical departments of neurology were interviewed. The data were analysed both quantitatively and qualitatively. RESULTS: In the participants' view, the quality of acute stroke care depends upon access to competent care, optimal acute management and the presence of trained and experienced personnel. Some subjective dimensions of service quality are dependent upon the interviewed neurologist's board certification status and the features of the respective department (stroke caseload, implementation of a stroke guideline). In comparison to national guidelines, early secondary prevention is underreported. Interviewed neurologists and guidelines agree on the importance of rapid diagnostic procedures and continuous monitoring. CONCLUSIONS: The focus upon early and rapid diagnosis and treatment underlines the importance of optimal emergency organisation for acute stroke patients. Early secondary prophylaxis, the prevention of complications and rehabilitation management are underestimated as relevant fields of action. Empirical research and medical education should address possible deficits concerning these aspects.


Subject(s)
Neurology/standards , Stroke/therapy , Certification , Germany , Humans , Legislation, Medical , Practice Guidelines as Topic , Quality Assurance, Health Care
5.
Z Arztl Fortbild Qualitatssich ; 100(4): 253-63, 2006.
Article in German | MEDLINE | ID: mdl-16878794

ABSTRACT

The application of evidence-based and standardized knowledge is an important basis for coordinated and effective clinical work. A multicenter study, which was conducted in 30 clinical neurology departments and included 99 junior and senior registrars, addressed aspects of practical knowledge of stroke treatment by open structured oral interviews which were analyzed with respect to interphysician and guideline conformity. In addition, the participants were asked to rate the usefulness of various informational sources and describe their informational sources used according to the aspects of practical knowledge addressed. The respective departmental directors were questioned about the sources of medical knowledge accessible in their clinic. In almost all hospitals, physicians had access to a library and the Internet. However, departments differed with respect to their information management (frequency and type of medical education, quality management, participation in research activities). In accordance with other studies, the knowledge sources reported most often were textbooks, journals and clinical studies. For most sources, the usefulness rankings largely corresponded to the rankings of user behavior. Both were only weak predictors for interphysician and guideline conformity. They are more closely related to the within-department homogeneity of practical knowledge than to interdepartmental and guideline conformity. Within-department homogeneity is enhanced by the use of recent, published and evidence-based sources and topical interaction with clinical colleagues. Guideline conformity was related to the use of databases and professional journals. A preference for colleagues from out-patient practices diminished both interphysician and guideline conformity. It seems there is still untapped potential for within-department knowledge management, such as medical education, implementation and use of guidelines and topical discussions, which may enhance the homogeneity and guideline conformity of the practical knowledge that clinicians apply.


Subject(s)
Controlled Clinical Trials as Topic/standards , Interprofessional Relations , Neurology/standards , Stroke/therapy , Communication , Evidence-Based Medicine/standards , Humans , Knowledge , Practice Guidelines as Topic
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