Cell culture based production of avian influenza vaccines

Vaccination of poultry can be used as a tool to control outbreaks of avian influenza, including that of highly pathogenic H5 and H7 strains. Influenza vaccines are traditionally produced in embryonated chicken eggs. Continuous cell lines have been suggested as an alternative substrate to produce influenza vaccines, as they are more robust and lack the long lead times associated with the production of large quantities of embryonated eggs. In the study that is described in this thesis, the production of influenza virus in cell culture was explored. Therefore, several cell lines were assessed for their ability to propagate influenza virus. Furthermore, adaptations to both cell line and seed virus were suggested that increased virus yield, thereby allowing the production of attenuated influenza virus strains.</p

Mutations in the M-Gene Segment Can Substantially Increase Replication Efficiency of NS1 Deletion Influenza A Virus in MDCK Cells

Influenza viruses unable to express NS1 protein (delNS1) replicate poorly and induce high amounts of interferon (IFN). They are therefore considered as candidate viruses for live-attenuated influenza vaccines. Their attenuated replication is generally assumed to result from the inability to counter the antiviral host response, as delNS1 viruses replicate efficiently in Vero cells, which lack IFN expression. In this study, delNS1 virus was parallel passaged on IFN competent MDCK cells, which resulted in two strains that were able to replicate to high virus titres in MDCK cells due to adaptive mutations in especially the M-gene segment, but also the NP and NS gene segments. Most notable were clustered U-to-C mutations in the M segment of both strains and clustered A-to-G mutations in the NS segment of one strain, which presumably resulted from host cell mediated RNA editing. The M segment mutations in both strains changed the ratio of M1 to M2 expression, probably by affecting splicing efficiency. In one virus, 2 amino acid substitutions in M1 additionally enhanced virus replication, possibly through changes in the M1 distribution between the nucleus and the cytoplasm. Both adapted viruses induced equal levels of IFN as delNS1 virus. These results show that the increased replication of the adapted viruses is not primarily due to altered IFN induction, but rather related to changes in M1 expression or localization. The mutations identified in this paper may be used to enhance delNS1 virus replication for vaccine production

Home care in Europe: a systematic literature review

<p>Abstract</p> <p>Background</p> <p>Health and social services provided at home are becoming increasingly important. Hence, there is a need for information on home care in Europe. The objective of this literature review was to respond to this need by systematically describing what has been reported on home care in Europe in the scientific literature over the past decade.</p> <p>Methods</p> <p>A systematic literature search was performed for papers on home care published in English, using the following data bases: Cinahl, the Cochrane Library, Embase, Medline, PsycINFO, Sociological Abstracts, Social Services Abstracts, and Social Care Online. Studies were only included if they complied with the definition of home care, were published between January 1998 and October 2009, and dealt with at least one of the 31 specified countries. Clinical interventions, instrument developments, local projects and reviews were excluded. The data extracted included: the characteristics of the study and aspects of home care 'policy & regulation', 'financing', 'organisation & service delivery', and 'clients & informal carers'.</p> <p>Results</p> <p>Seventy-four out of 5,133 potentially relevant studies met the inclusion criteria, providing information on 18 countries. Many focused on the characteristics of home care recipients and on the organisation of home care. Geographical inequalities, market forces, quality and integration of services were also among the issues frequently discussed.</p> <p>Conclusions</p> <p>Home care systems appeared to differ both between and within countries. The papers included, however, provided only a limited picture of home care. Many studies only focused on one aspect of the home care system and international comparative studies were rare. Furthermore, little information emerged on home care financing and on home care in general in Eastern Europe. This review clearly shows the need for more scientific publications on home care, especially studies comparing countries. A comprehensive and more complete insight into the state of home care in Europe requires the gathering of information using a uniform framework and methodology.</p

De jeugdzorgboerderij : een wenkend perspectief

De Jeugdzorgboerderij is een vrij nieuwe, maar snel groeiende product-marktcombinatie binnen landbouw en zorg. In verschillende provincies zijn, onder impulsen van agrarische ondernemers, jeugdzorginstellingen en LTO, Jeugdzorgboerderijen ontwikkeld. Om uitwisseling en afstemming tussen de verschillende initiatieven te bevorderen is het Platform Jeugdzorgboerderijen opgericht. In deze publicatie wordt eerst ingegaan op de Jeugdzorgboerderij, aan de hand van verschillende aspecten wordt deze belicht. Vervolgens wordt ingegaan op de kwaliteiten en effecten van verschillende vormen van jeugdzorg op de boerderi

Primmorphs from seven marine sponges : formation and structure

Primmorphs were obtained from seven different marine sponges: Stylissa massa, Suberites domuncula, Pseudosuberites aff. andrewsi, Geodia cydonium, Axinella polypoides, Halichondria panicea and Haliclona oculata. The formation process and the ultra structure of primmorphs were studied. A positive correlation was found between the initial sponge-cell concentration and the size of the primmorphs. By scanning electron microscopy (SEM) it was observed that the primmorphs are very densely packed sphere-shaped aggregates with a continuous pinacoderm (skin cell layer) covered by a smooth, cuticle-like structure. In the presence of amphotericin, or a cocktail of antibiotics (kanamycin, gentamycin, tylosin and tetracyclin), no primmorphs were formed, while gentamycin or a mixture of penicillin and streptomycin did not influence the formation of primmorphs. The addition of penicillin and streptomycin was, in most cases, sufficient to prevent bacterial contamination, while fungal growth was unaffected

Alle beestjes helpen. Onderzoek naar achteruitgang van insecten in Nederland

Contains fulltext : 199785.pdf (publisher's version ) (Open Access)15 p

Effect of natural and chimeric haemagglutinin genes on influenza A virus replication in baby hamster kidney cells.

Baby hamster kidney (BHK21) cells are used to produce vaccines against various viral veterinary diseases, including rabies and foot-and-mouth-disease. Although particular influenza virus strains replicate efficiently in BHK21 cells the general use of these cells for influenza vaccine production is prohibited by the poor replication of most strains, including model strain A/PR/8/34 [H1N1] (PR8). We now show that in contrast to PR8, the related strain A/WSN/33 [H1N1] (WSN) replicates efficiently in BHK21 cells. This difference is determined by the haemagglutinin (HA) protein since reciprocal reassortant viruses with swapped HAs behave similarly with respect to growth on BHK21 cells as the parental virus from which their HA gene is derived. The ability or inability of six other influenza virus strains to grow on BHK21 cells appears to be similarly dependent on the nature of the HA gene since reassortant PR8 viruses containing the HA of these strains grow to similar titres as the parental virus from which the HA gene was derived. However, the growth to low titres of a seventh influenza strain was not due to the nature of the HA gene since a reassortant PR8 virus containing this HA grew efficiently on BHK21 cells. Taken together, these results suggest that the HA gene often primarily determines influenza replication efficiency on BHK21 cells but that in some strains other genes are also involved. High virus titres could be obtained with reassortant PR8 strains that contained a chimeric HA consisting of the HA1 domain of PR8 and the HA2 domain of WSN. HA1 contains most antigenic sites and is therefore important for vaccine efficacy. This method of producing the HA1 domain as fusion to a heterologous HA2 domain could possibly also be used for the production of HA1 domains of other viruses to enable the use of BHK21 cells as a generic platform for veterinary influenza vaccine production

MDCK cell line with inducible allele B NS1 expression propagates deINS1 inflenza virus to high titres

Influenza A viruses lacking the gene encoding the non-structural NS1 protein (delNS1) have potential use as live attenuated vaccines. However, due to the lack of NS1, virus replication in cell culture is considerably reduced, prohibiting commercial vaccine production. We therefore established two stable MDCK cell lines that show inducible expression of the allele B NS1 protein. Upon induction, both cell lines expressed NS1 to about 1000-fold lower levels than influenza virus-infected cells. Nevertheless, expression of NS1 increased delNS1 virus titres to levels comparable to those obtained with an isogenic virus strain containing an intact NS1 gene. Recombinant NS1 expression increased the infectious virus titres 244 to 544-fold and inhibited virus induced apoptosis. However, NS1 expression resulted in only slightly, statistically not significant, reduced levels of interferon-ß production. Thus, the low amount of recombinant NS1 is sufficient to restore delNS1 virus replication in MDCK cells, but it remains unclear whether this occurs in an interferon dependent manner. In contrast to previous findings, recombinant NS1 expression did not induce apoptosis, nor did it affect cell growth. These cell lines thus show potential to improve the yield of delNS1 virus for vaccine production