Age stratified seroepidemiological studies play a crucial role in the design and assessment of vaccination strategies. An existing multiplex bead immunoassay for measles, mumps, rubella and varicella zoster virus antibodies together with a newly developed multiplex bead immunoassay for herpes simplex virus type 1 and type 2 antibodies were used to investigate the age-related seroepidemiology of these viruses in England during 2012.To develop the HSV-1 and HSV-2 antibody assay, attempts were made to produce full length of HSV-1 and HSV-2 glycoprotein G using a baculovirus vector expression system. While HSV-1 gG protein was produced, the proteins were extensively aggregated. Native glycoprotein G molecules undergo partial removal of HSV-1 signal sequence and HSV-1 short membrane anchor sequence during post translational modification. It is possible that such post translational modification is not performed when protein is processed in insect cell culture. Attempts to produce an HSV-2 glycoprotein G were not successful. It is possible that the high GC-content of HSV-2 glycoprotein G led to poor fidelity of copying the PCR amplification sequence. Commercially available truncated HSV-1 gG and HSV-2 gG were therefore used to develop a duplex microbead immunoassay for the simultaneous detection of specific HSV antibodies in human sera. The resultant assays performed with low sensitivity and specificity (HSV-1 of 89% and 66%, respectively and for HSV-2 of 79% and 85%, respectively) compared to the reference HerpeSelect ELISA.The MMRV multiplex bead immunoassay proved rapid, and required minimal sample volume to semi-quantify MMRV specific antibodies. The seroepidemiology of MMR results was compared with previous seroepidemiological studies performed in 1996 in England. The comparison showed an increase in the proportion of individuals who were positive for mumps and measles antibodies in the 2012 survey. The proportion of individuals positive for rubella was essentially unchanged. The increase in the proportion of individuals positive for mumps and measles antibodies in 2012 show the effectiveness of the change in MMR vaccination policy for England from 1996 onward. For VZV, the proportion of individuals who were positive for varicella antibodies between the 1996 and 2012 serological surveys were essentially unchanged. The comparison showed that most young children are susceptible to VZV. At this level of immunity, it can be expected that varicella will continue to produce epidemics of infection in the population, unless varicella vaccination is implemented as a part of routine childhood vaccination.

O desenvolvimento de vacinas contra a raiva tão eficientes quanto as atuais ainda é considerado importante para a profilaxia dessa doença devido ao alto número de mortes por ano no mundo. Este trabalho mostra dois sistemas para a expressão recombinante do principal antígeno da raiva, a glicoproteína viral (RVGP): células Schneider 2 de Drosophila melanogaster estavelmente transfectadas (S2 rRVGP) e vírus Semliki Forest (SFV) carregando o RNA da RVGP (SFVRVGP). Ensaios de purificação por cromatografia de afinidade, da rRVGP de S2 rRVGP produzida em biorreator, demonstraram resultados promissores para o isolamento de monômeros da rRVGP. Para os estudos de imunogenicidade, camundongos foram vacinados com rRVGP de S2 rRVGP e SFV-RVGP. Dosagem de anticorpos anti-glicoproteína do vírus da raiva, neutralizantes, IgG1 e IgG2a, e citocinas demonstraram que o SFV-RVGP induziu predominantemente uma resposta imune do tipo celular e que os dois vetores foram capazes de expressar uma rRVGP imunogênica, apresentando um potencial uso clínico (veterinário e humano). / The development of new and equally efficient rabies vaccines is still considered important to the prophylaxis of the disease, which is responsible for many deaths per year worldwide. This work used two systems for recombinant expression of the major rabies antigen, the viral glycoprotein (RVGP): stably transfected Drosophila melanogaster Schneider 2 cells (S2 rRVGP) and Semliki Forest Virus (SFV) carrying the RNA of RVGP (SFV-RVGP). Purification assays of the rRVGP by metal ion affinity chromatography, from S2 rRVGP cells produced in bioreactor, showed promising results for rRVGP monomers isolation. Analysis of antibodies anti-rabies virus glycoprotein, neutralizing, IgG1 and IgG2a, and citokines showed that the SFV-RVGP induced predominantly a cellular immune response, and both vectors were capable of expressing an immunogenic rRVGP, what reinforces potential clinical applications (veterinary or human).

Linhagem de células de inseto S2 foram cultivadas em meio TC100 suplementado em reator bubble free de 1.5 L e para estudar o seu crescimento e expressão da glicoproteína G do vírus da raiva (RVGP). Os dados permitiram propor um modelo matemático que reproduz o crescimento e produção da glicoproteína e que considera oito variáveis de estado e vinte parâmetros cinéticos. O modelo considera a velocidade específica de crescimento limitada por glicose, glutamina e glutamato e inibida por NH4+; consumo e formação de glutamina; velocidade específica de morte limitada por NH4+ e inibida por glicose; velocidade específica de produção de NH4+ e de GPV associada ao crescimento e a degradação de GPV. As concentrações de oxigênio dissolvido (pO2), glicose e glutamina foram modificadas para se avaliar a sua influência na velocidade específica de crescimento máxima e nos fatores de conversão. Os parâmetros do modelo foram ajustados usando a técnica de otimização dos poliedros flexíveis e as equações diferenciais do modelo foram integradas pelo método de Gear. / S2 cell strain from Drosophila melanogaster were cultivated in supplemented TC100 media in reactor \"bubble free\" to study their growth and expression of glycoprotein G of rabies virus (RVGP). The data allowed proposing a mathematical model that reproduces the growth and production of glycoprotein and that consider eight state variables and twenty kinetic parameters. The model considers the specific growth rate limited by glucose glutamine and glutamate and inhibited by NH4+ consumption and formation of glutamine, specific death rate limited by NH4+ and inhibited by glucose; production specific rate of NH4+ and RGPV associated with growth and degradation of RGPV. The concentrations of dissolved oxygen (pO2), glucose and glutamine were varied to evaluate their influence on maximum specific growth rate and conversion factors. The model parameters were adjusted using the flexible polyhedron optimization method and the differential equations of the model were integrated by the method of Gear.

Linhagem de células de inseto S2 foram cultivadas em meio TC100 suplementado em reator bubble free de 1.5 L e para estudar o seu crescimento e expressão da glicoproteína G do vírus da raiva (RVGP). Os dados permitiram propor um modelo matemático que reproduz o crescimento e produção da glicoproteína e que considera oito variáveis de estado e vinte parâmetros cinéticos. O modelo considera a velocidade específica de crescimento limitada por glicose, glutamina e glutamato e inibida por NH4+; consumo e formação de glutamina; velocidade específica de morte limitada por NH4+ e inibida por glicose; velocidade específica de produção de NH4+ e de GPV associada ao crescimento e a degradação de GPV. As concentrações de oxigênio dissolvido (pO2), glicose e glutamina foram modificadas para se avaliar a sua influência na velocidade específica de crescimento máxima e nos fatores de conversão. Os parâmetros do modelo foram ajustados usando a técnica de otimização dos poliedros flexíveis e as equações diferenciais do modelo foram integradas pelo método de Gear. / S2 cell strain from Drosophila melanogaster were cultivated in supplemented TC100 media in reactor \"bubble free\" to study their growth and expression of glycoprotein G of rabies virus (RVGP). The data allowed proposing a mathematical model that reproduces the growth and production of glycoprotein and that consider eight state variables and twenty kinetic parameters. The model considers the specific growth rate limited by glucose glutamine and glutamate and inhibited by NH4+ consumption and formation of glutamine, specific death rate limited by NH4+ and inhibited by glucose; production specific rate of NH4+ and RGPV associated with growth and degradation of RGPV. The concentrations of dissolved oxygen (pO2), glucose and glutamine were varied to evaluate their influence on maximum specific growth rate and conversion factors. The model parameters were adjusted using the flexible polyhedron optimization method and the differential equations of the model were integrated by the method of Gear.

The aim of this study was to increase the understanding of the mechanisms regulating cell proliferation and recombinant protein production in serum-free cultures of Trichoplusia ni (T. ni) insect cells. Conditioned medium (CM) was shown to contain both stimulatory and inhibitory factors (CM factors) influencing cell growth. Metalloproteinase (MP) activity was the major factor responsible for the growth stimulating effect of CM as shown by using the specific MP inhibitor DL-thiorphan. MPs may exist in several different molecular mass forms due to autoproteolysis. Although the main band of the MP was determined to be around 48 kDa, precursor forms above 48 kDa as well as autocatalytic degradation products below the main band could be observed. It is not clear whether all forms of the MP or just the main band is involved in the growth regulation. Further, a proteinase inhibitor could be identified in the inhibitory fraction. Thus, we speculate that the proteinase inhibitor may be part of an autocrine system regulating cell proliferation. Analysis of the cell cycle phase distribution revealed a high proportion of cells in the G1 (80-90 %) and a low proportion of cells in the S and G2/M phases (10-20 %) during the whole culture, indicating that S and G2/M are short relative to G1. After inoculation, a drastic decrease in the S phase population together with a simultaneous increase of cells in G1 and G2/M could be observed as a lagphase on the growth curve and this may be interpreted as a temporary replication stop. When the cells were released from the initial arrest, the S phase population gradually increased again. This was initiated earlier in CM-supplemented cultures, and agrees with the earlier increase in cell concentration. Thus, these data suggests a correlation between CM factors and the cell cycle dynamics. In cultures supplied with CM, a clear positive effect on specific productivity was observed, with a 30 % increase in per cell productivity. The specific productivity was also maintained at a high level much longer time than in fresh-medium cultures. The positive effect observed after 20 h coincided with the time a stimulatory effect on cell growth first was seen. Thus, the productivity may be determined by the proliferation potential of the culture. A consequence of this would be that the secreted MP indirectly affects productivity. Finally, the yeast extract from Express Five SFM contains factors up to 35 kDa which are essential for T. ni cell growth. The optimal concentration was determined to be 2.5-fold that in normal medium, while higher concentrations were inhibitory. However although vital, they were not solely responsible for the growth-enhancing effect, as some other, more general, component present in yeast extract was needed for proliferation as well. / <p>QC 20101129</p>

The aim of this work has been to characterize the effects of conditioned medium (CM) on insect cell productivity and physiology in order to get a better understanding about the mechanisms that regulate productivity in serum-free media. Two cell lines have been investigated, Spodoptera frugiperda (Sf9) and Trichoplusia ni (T. ni, BTI-Tn-5B1-4). The baculovirus expression vector system (BEVS) was used for protein expression, using the ligand-binding domain of the human glucocorticoid receptor as a model protein. Addition of CM at inoculation led to a shorter lag phase and that the cells reached the maximum cell density faster than cells in fresh medium for both Sf9 and T. ni cells. Sf9 cells passed a switch in growth kinetics after 30-40 passages. At this point, CM lost its stimulating effect on proliferation. CM also affected the cell size and cell cycle progression. Sf9 and T. ni cells became smaller when CM was added at inoculation because they had a minor arrest in the cell cycle after inoculation and therefore started to divide earlier than cells in fresh medium. For Sf9 cells, this was illustrated by a smaller arrest in G2/M in the beginning of culture and the cells were consequently less synchronized. For T. ni cells, the initial decrease in the S phase population was followed by an earlier increase of the S phase population for the cells with CM than for the cells in fresh medium. Addition of 20 % CM or CM filtrated with a 10 kDa cut-off filter to Sf9 cultures had a negative effect on the specific productivity. However, addition of CM to Sf9 cells that had passed the switch in growth kinetics had no negative effect on productivity. This indicates that CM not affects the protein production per se, but rather through its effects on cell physiology. Instead, the degree of cells synchronized in G2/M is important for high productivity and the gradually decreasing degree of synchronization during the course of a culture might be the explanation behind the cell density dependent decrease in productivity for Sf9 cells. This was further supported by the positive effects on productivity achieved by synchronizing Sf9 cells in G2/M by yeastolate limitation, which counteracted the cell density-dependent drop in productivity and hence a higher volumetric yield was achieved. Addition of 20 % CM to T. ni cultures had a positive effect on productivity. The specific productivity was maintained at a high level longer than for cells in 100 % fresh medium. The product concentration was 34 % higher and the maximum product concentration was obtained 24 hours earlier for the cells with the addition of CM. These results show that the effects of CM on productivity are not the same for the two cell lines and that the mechanism regulating productivity are quite complex. / QC 20101125

No description available.

Human α-N-Acetylglucosaminidase (Naglu) is a lysosomal acid hydrolase implicated in tthe rare metabolic storage disorder known as mucopolysaccharidosis type IIIB (MPS IIIB; also Sanfilippo syndrome B). Absence of this enzyme results in cytotoxic accumulation of heparan sulphate in the central nervous system, causing mental retardation and a shortened lifespan. Enzyme replacement therapy is not currently effective to treat neurological symptoms due to the inability of exogenous Naglu to access the brain. This laboratory uses a Spodoptera frugiperda (Sf9) insect cell system to express Naglu fused to a synthetic protein transduction domain with the intent to facilitate delivery of Naglu across the blood-brain barrier. The project described herein may be broken down into three main sections. Firstly, the impact of two cryptic splice sites on Naglu expression levels was analyzed in both transiently expressing Sf9 cultures and stably selected cell lines. Secondly, the effectiveness of the native Naglu secretion-signaling peptide in the Sf9 system was examined. Finally, purification of a Naglu fusion protein from suspension culture medium was performed using hydrophobic interaction chromatographic techniques. The ultimate goal of this research is to develop an efficient system for economical, large-scale production of a human recombinant Naglu fusion protein that has the potential to be successfully used for enzyme replacement therapy to treat MPS IIIB. / Graduate