The chicken BG system is a highly polymorphic and polygenic multigene family encoding type I transmembrane proteins, with butryophilins as homologues in mammals, some of which are crucial in T cell regulation. There are three genomic locations where BG genes are found: one singleton BG gene (BG0) on chromosome 2, another singleton gene (BG1) in BF-BL region (the so-called minimal essential chicken MHC) on chromosome 16, and many BG genes arranged tandemly in the BG region just outside the MHC. BG genes in BG region have copy number variation between different chicken haplotypes, so it has been unclear which BG genes are alleles, as very little sequence information has been available for haplotypes other than B12, the best characterized one. Also, the functions of chicken BG genes have been a mystery for half a century, although there is evidence for cytoskeletal regulation and for viral disease resistance. Therefore, the aim of the research was to develop new procedures and reagents to understand the BG system. A novel PCR protocol was established to overcome the difficulty of amplifying full length polymorphic BG transcripts, and then was applied to systematically examine the BG cDNA sequences from T cells and B cells of four different chicken haplotypes. In total 23 BG genes were found, most with alternative splicing isoforms; most strikingly, the transcripts potentially encoding soluble BG proteins were only seen in B cells, indicating functional differences of the same gene in T and B cells. By comparing the dominantly expressed BG genes as 'functional alleles' in these cells, only the cytoplasmic tail region is clearly seen to be under selection, based on the overwhelming preponderance of non-synonymous changes. With many other unexpected findings discovered in this project, a clearer picture of chicken BG genes is presented, and more questions were raised for future study. In order to explore BG functions and further characterize BG proteins, fourteen stable cell lines were developed expressing fusion proteins of the Ig-V domains of the 14 BG genes from the B12 haplotype chicken with the human IgG1 Fc fragment. These BG-Fc fusion proteins were used in sandwich enzyme-linked immunosorbent assays (ELISAs) to screen 290 BG monoclonal antibody (mAb) tissue culture supernatants, and these BG mAbs were further characterized for specificity by western blot using BG-Fc fusion proteins. These solid tools (BG-Fc fusion proteins and BG mAbs) provide the basis to further understand chicken BG functions and answer other interesting questions.

Therapeutic proteins, a.k.a. biopharmaceuticals, are most commonly produced in expression systems derived from Chinese Hamstery Ovary (CHO) cells, thanks to great capacity of post-translational modifications like secretation, folding and glycosylation. The engineering of cells for regulation of protein expression has many options including knock-in and knock-out of genes, epigenetic studies or improvement of the expression casette of the protein of interest by e.g. promotor variants or modifications of the 5’ and 3’ untranslated region (UTR). The 3’-UTR is therefore a good optimization candidate for attempting to achieve increased expression of therapeutic proteins. The final aim of this study was to identify and design 3’-UTRs for improved expression of therapeutic proteins in HyClone™ CHO cells from GE Healthcare Bio-Sciences AB (GEHC). The impact goal is to increase the efficiency and lower the costs for pharmaceutical companies when producing biopharmaceuticals in the HyClone™ CHO cell line, leading to increased accessibility of monoclonal antibodies (mAbs) on the pharmaceutical market. The study was initiated with bioinformatic analysis of the CHO cell transcriptome from a set of RNA-seq data of HyClone™ CHO to find high expressing, context independent genes. The 3’-UTRs from the best candidate genes were used for construction of plasmids for expression of a Fc-eGFP fusion protein. Nine selected 3’-UTRs were designed, synthesized and cloned into a parent plasmid (pGE0520) creating nine plasmid variants (pGE0523-531). The constructed plasmids were used for evaluation with site directed integration (SDI) into the HyClone™ CHO cell line and expression analysis were performed by flow cytometry and antibody titer measurements from cells with successfully integrated plasmid sorted by fluorescence-activated cell sorting (FACS).   Result show a significant effect on protein expression when using different variants of 3’-UTRs. Two variants, pGE0524 and pGE0526, competing with the parent plasmid in expression levels and integration efficiency from SDI, making them candidates for further investigations against the parent plasmid. Results also show good correlation between flow cytometry data from pre- and post-sorting, which can make research for further 3’-UTRs more efficient by evaluations and prediction of expression levels before cell sorting.

Main purpose of this study was to increase protein expression in Chinese hamster ovary (CHO) cells by improving protein secretion of translated proteins. The goal was to find signal peptides from the screening of signal peptide libraries for improvement of protein secretion using a CHO-cell express selection system. Biopharmaceutical products, proteins such as monoclonal antibodies (mAbs), are most commonly produced using mammalian expression systems such as the expression in CHO cells. The posttranslational modifications of the proteins being expressed in CHO cells are similar to the expressional modifications in human cells, why the CHO cells are suitable for production of proteins used for human therapy. The expression of proteins in the cell is a complex mechanism, fundamentally depending on the DNA sequences in the cell nucleus. Secretion of translated proteins has been showed to be a bottleneck when improving expression. Secretion is initiated by the signal peptide, a n-terminal prolongation of the protein that is recognized by a signal recognition particle (SRP) when being translated by the ribosome. The sequence and structure of the signal peptide has been proved to affect secretion and altering the signal peptide could improve secretion even when changing signal peptide between different species. Designing variants of the signal peptides and analyzing protein expression might lead to improvements of the construct design and more protein produced from the cells, which would save time, money and material for the producer. To construct plasmids containing the gene of interest (GOI) and different signal peptides, several gene cloning methods were used. The plasmids were amplified using Escherichia coli (E. coli) transformation. The constructs were expressed by transfection into the CHO cell genome, and expression were analyzed using flow cytometry. When analyzing expression of a Fc-fusion protein with 5 different signal peptides, the signal peptide Azurocidin is the one showing highest expression levels in this study. In addition, IgG kapa and Albumin signal peptides did not show as high protein expression levels, even if they were better than the L1d and H5b signal peptides. Since signal peptides are exchangeable between proteins and species, it might be that Azurocidin is improving secretion and protein expression with other proteins than Fc-fusion proteins which would be an interesting aspect for further studies. When altering signal peptides with library sequences, the experimental challenges were crucial for the protein expression results and due to these issues, no library sequence could be seen to conquer others when it comes to protein expression levels. Transfection and cultivation procedures needs to be studied and improved before being able to draw conclusions about which signal peptide library sequences that might improve secretion and increase the protein expression.

No description available.

Introdução: O fragmento amino-terminal do pró-peptídeo natriurético do tipo B (NT-proBNP) é um forte marcador de doença cardiovascular com evidências recentes de que a inflamação também pode influenciar seus valores. A diferenciação dessa variável de confusão é de particular interesse nas doenças reumáticas. Objetivos: Avaliar o comportamento dos valores de NT-proBNP em pacientes com espondilite anquilosante (EA) pré e pós uso de bloqueadores de TNF para determinar a possível associação entre os valores de NT-proBNP e os parâmetros inflamatórios. Métodos: Quarenta e cinco pacientes consecutivos com EA sem evidência prévia ou atual de doença cardiovascular ou disfunção miocárdica sistólica e que eram elegíveis para terapia anti-TNF foram incluídos prospectivamente. Todos os pacientes receberam bloqueadores de TNF e foram avaliados para concentrações circulantes de NT-proBNP, parâmetros clínicos e laboratoriais de atividade de doença, fatores de risco cardiovasculares tradicionais e ecodopplercardiografia convencional e tecidual no momento da inclusão e após seis meses de tratamento. Resultados: No momento da inclusão, todos os pacientes tinham EA ativa, os valores de NT-proBNP tinham uma mediana de 36 (20-72) pg/mL e 11% dos valores estavam altos mesmo na ausência de alteração miocárdica sistólica. A análise de regressão linear múltipla revelou que esse peptídeo estava independentemente correlacionado com o VHS (p < 0,001), com a idade dos pacientes (p = 0,01) e com a pressão de pulso (p = 0,01) no momento da inclusão. Após seis meses, todos os parâmetros relacionados a doença de base melhoraram e os valores de NT-proBNP se reduziram significativamente [24 (16-47) pg/mL, p = 0,037] quando comparados com os valores do momento da inclusão. As mudanças nos valores de NT-proBNP correlacionaram-se positivamente com as mudanças nos valores do VHS (r = 0,41, p = 0.006). Os fatores de risco cardiovasculares avaliados permaneceram estáveis durante o seguimento. Conclusão: As elevações nos valores de NT-proBNP devem ser interpretadas com cuidado nos pacientes com EA ativa e sem evidência de doença cardiovascular. A redução no curto prazo dos valores de NT-proBNP nesses pacientes recebendo terapia anti-TNF parece refletir uma melhora do estado inflamatório / Introduction: N-terminal pro-brain natriuretic peptide (NT-proBNP) is a strong marker of cardiovascular disease with recent evidence that inflammation may also influence its levels; discrimination of this confounding variable is of particular interest in rheumatic diseases. Objectives: to evaluate NT-proBNP in ankylosing spondylitis (AS) patients pre- and post-TNF blocker to determine the possible association between NT-proBNP levels and inflammatory parameters. Methods: Forty-five consecutive AS patients without previous/current cardiovascular disease or systolic myocardial dysfunction, who were eligible to anti-TNF therapy, were prospectively enrolled. All patients received TNF blockers and they were evaluated for circulating NT-proBNP levels, clinical and laboratory parameters of disease activity, traditional cardiovascular risk factors, and conventional and tissue Doppler imaging echocardiography at baseline (BL) and six months after (6M) treatment. Results: At BL, all patients had active AS, NT-proBNP levels had a median of 36 (20-72) pg/mL and 11% were high in spite of no systolic alteration. Multiple linear regression analysis revealed that this peptide, at BL, was independently correlated with ESR (p < 0.001), age (p = 0.01) and pulse pressure (p = 0.01). After 6M, all disease parameters improved and NT-proBNP levels were significantly reduced [24 (16-47) pg/mL, p = 0.037] compared to BL. Changes in NT-proBNP were positively correlated with ESR changes (r = 0.41, p = 0.006). Cardiovascular risk factors remained stable during follow-up. Conclusion: our data suggests that elevations of NT-proBNP should be interpreted with caution in active AS patients with no other evidence of cardiovascular disease. The short-term reduction of NT-proBNP levels in these patients receiving anti-TNF therapy appears to reflect an improvement in inflammatory status

Introdução: O fragmento amino-terminal do pró-peptídeo natriurético do tipo B (NT-proBNP) é um forte marcador de doença cardiovascular com evidências recentes de que a inflamação também pode influenciar seus valores. A diferenciação dessa variável de confusão é de particular interesse nas doenças reumáticas. Objetivos: Avaliar o comportamento dos valores de NT-proBNP em pacientes com espondilite anquilosante (EA) pré e pós uso de bloqueadores de TNF para determinar a possível associação entre os valores de NT-proBNP e os parâmetros inflamatórios. Métodos: Quarenta e cinco pacientes consecutivos com EA sem evidência prévia ou atual de doença cardiovascular ou disfunção miocárdica sistólica e que eram elegíveis para terapia anti-TNF foram incluídos prospectivamente. Todos os pacientes receberam bloqueadores de TNF e foram avaliados para concentrações circulantes de NT-proBNP, parâmetros clínicos e laboratoriais de atividade de doença, fatores de risco cardiovasculares tradicionais e ecodopplercardiografia convencional e tecidual no momento da inclusão e após seis meses de tratamento. Resultados: No momento da inclusão, todos os pacientes tinham EA ativa, os valores de NT-proBNP tinham uma mediana de 36 (20-72) pg/mL e 11% dos valores estavam altos mesmo na ausência de alteração miocárdica sistólica. A análise de regressão linear múltipla revelou que esse peptídeo estava independentemente correlacionado com o VHS (p < 0,001), com a idade dos pacientes (p = 0,01) e com a pressão de pulso (p = 0,01) no momento da inclusão. Após seis meses, todos os parâmetros relacionados a doença de base melhoraram e os valores de NT-proBNP se reduziram significativamente [24 (16-47) pg/mL, p = 0,037] quando comparados com os valores do momento da inclusão. As mudanças nos valores de NT-proBNP correlacionaram-se positivamente com as mudanças nos valores do VHS (r = 0,41, p = 0.006). Os fatores de risco cardiovasculares avaliados permaneceram estáveis durante o seguimento. Conclusão: As elevações nos valores de NT-proBNP devem ser interpretadas com cuidado nos pacientes com EA ativa e sem evidência de doença cardiovascular. A redução no curto prazo dos valores de NT-proBNP nesses pacientes recebendo terapia anti-TNF parece refletir uma melhora do estado inflamatório / Introduction: N-terminal pro-brain natriuretic peptide (NT-proBNP) is a strong marker of cardiovascular disease with recent evidence that inflammation may also influence its levels; discrimination of this confounding variable is of particular interest in rheumatic diseases. Objectives: to evaluate NT-proBNP in ankylosing spondylitis (AS) patients pre- and post-TNF blocker to determine the possible association between NT-proBNP levels and inflammatory parameters. Methods: Forty-five consecutive AS patients without previous/current cardiovascular disease or systolic myocardial dysfunction, who were eligible to anti-TNF therapy, were prospectively enrolled. All patients received TNF blockers and they were evaluated for circulating NT-proBNP levels, clinical and laboratory parameters of disease activity, traditional cardiovascular risk factors, and conventional and tissue Doppler imaging echocardiography at baseline (BL) and six months after (6M) treatment. Results: At BL, all patients had active AS, NT-proBNP levels had a median of 36 (20-72) pg/mL and 11% were high in spite of no systolic alteration. Multiple linear regression analysis revealed that this peptide, at BL, was independently correlated with ESR (p < 0.001), age (p = 0.01) and pulse pressure (p = 0.01). After 6M, all disease parameters improved and NT-proBNP levels were significantly reduced [24 (16-47) pg/mL, p = 0.037] compared to BL. Changes in NT-proBNP were positively correlated with ESR changes (r = 0.41, p = 0.006). Cardiovascular risk factors remained stable during follow-up. Conclusion: our data suggests that elevations of NT-proBNP should be interpreted with caution in active AS patients with no other evidence of cardiovascular disease. The short-term reduction of NT-proBNP levels in these patients receiving anti-TNF therapy appears to reflect an improvement in inflammatory status