The simian immunodeficiency virus Δnef vaccine, after application to the tonsils of rhesus macaques, replicates primarily within CD4+ T cells and elicits a local perforin-positive CD8+ T-cell response

Deletion of the nef gene from simian immunodeficiency virus (SIV) strain SIVmac239 yields a virus that undergoes attenuated growth in rhesus macaques and offers substantial protection against a subsequent challenge with some SIV wild-type viruses. We used a recently described model to identify sites in which the SIVΔnef vaccine strain replicates and elicits immunity in vivo. A high dose of SIVΔnef was applied to the palatine and lingual tonsils, where it replicated vigorously in this portal of entry at 7 days. Within 2 weeks, the virus had spread and was replicating actively in axillary lymph nodes, primarily in extrafollicular T-cell-rich regions but also in germinal centers. At this time, large numbers of perforin-positive cells, both CD8+ T cells and CD3-negative presumptive natural killer cells, were found in the tonsil and axillary lymph nodes. The number of infected cells and perforin-positive cells then fell. When autopsy studies were carried out at 26 weeks, only 1 to 3 cells hybridized for viral RNA per section of lymphoid tissue. Nevertheless, infected cells were detected chronically in most lymphoid organs, where the titers of infectious virus could exceed by a log or more the titers in blood. Immunocytochemical labeling at the early active stages of infection showed that cells expressing SIVΔnef RNA were CD4+ T lymphocytes. A majority of infected cells were not in the active cell cycle, since 60 to 70% of the RNA-positive cells in tissue sections lacked the Ki-67 cell cycle antigen, and both Ki-67-positive and -negative cells had similar grain counts for viral RNA. Macrophages and dendritic cells, identified with a panel of monoclonal antibodies to these cells, were rarely infected. We conclude that the attenuated growth and protection observed with the SIVΔnef vaccine strain does not require that the virus shift its characteristic site of replication, the CD4+ T lymphocyte. In fact, this immunodeficiency virus can replicate actively in CD4+ T cells prior to being contained by the host, at least in part by a strong killer cell response that is generated acutely in the infected lymph nodes

Agenda praktijkgericht onderzoek health:Topsector Life Sciences & Health

De Regiegroep van de topsector Life Sciences & Health wil een impuls geven aan initiatieven die praktijkgericht onderzoek op het gebied van Health betreffen. De redenen hiervoor zijn de relatief bescheiden positie van Health vergeleken bij de Life Sciences in de eerdere agendering onder de topsector en de verwachting dat praktijkgericht onderzoek door hogescholen een substantiële bijdrage kan leveren aan de doelstellingen onder het topsectorenbeleid. Daarom is opdracht gegeven tot het opstellen van een agenda voor praktijkgericht onderzoek “Health”. Deze agenda moet leiden tot samenwerking met een solide economische component tussen hogescholen, eventuele andere kennisinstellingen en publieke en private partijen uit de beroepspraktijk. De Agenda Praktijkgericht Onderzoek Health is ingedeeld in vier overkoepelende thema’s (A - D) waarop het onderzoek van hogescholen zich zou moeten richten. Binnen elk thema zijn onderwerpen benoemd die op basis van deze verkenning prioriteit verdienen

A critical appraisal of the potential benefit of post-operative structured follow-up after resection for biliary tract cancer

BACKGROUND: There is currently no evidence to support structured use of imaging or biomarkers during follow-up of patients after curative resection of biliary tract cancer (BTC). Besides, the influence of early detection of recurrence and subsequent start of palliative chemotherapy on overall survival remains unknown. The aim of this study is to describe and compare the results of two follow-up strategies. METHODS: This retrospective multicenter cohort study compared patients from the Amsterdam UMC undergoing pragmatic clinical follow-up, to patients from the observational cohort of the BILCAP study undergoing structured follow-up. Primary outcome was overall survival. RESULTS: A total of 315 patients were included n=91 pragmatic, n=224 structured follow-up). At median follow-up of 56.9 months, 189 (60%) patients were diagnosed with recurrence. After recurrence, more patients received palliative (chemo) therapy in the structured group (43% vs 75%, P<0.001). Median overall survival was lower in the pragmatic group (27.7 vs 39.1 months, P=0.003). Median overall survival of patients who actually received chemotherapy was comparable (27.2 vs 27.7 months, P=0.574). CONCLUSION: This study describes the results of two follow-up strategies. Although these groups are biased, it is noted that after pragmatic follow-up fewer patients received palliative chemotherapy but that those who actually received chemotherapy had similar overall survival compared to patients undergoing structured follow-up

Peroxicretion: a novel secretion pathway in the eukaryotic cell

Background: Enzyme production in microbial cells has been limited to secreted enzymes or intracellular enzymes followed by expensive down stream processing. Extracellular enzymes consists mainly of hydrolases while intracellular enzymes exhibit a much broader diversity. If these intracellular enzymes could be secreted by the cell the potential of industrial applications of enzymes would be enlarged. Therefore a novel secretion pathway for intracellular proteins was developed, using peroxisomes as secretion vesicles. Results: Peroxisomes were decorated with a Golgi derived v-SNARE using a peroxisomal membrane protein as an anchor. This allowed the peroxisomes to fuse with the plasma membrane. Intracellular proteins were transported into the peroxisomes by adding a peroxisomal import signal (SKL tag). The proteins which were imported in the peroxisomes, were released into the extracellular space through this artificial secretion pathway which was designated peroxicretion. This concept was supported by electron microscopy studies. Conclusion: Our results demonstrate that it is possible to reroute the intracellular trafficking of vesicles by changing the localisation of SNARE molecules, this approach can be used in in vivo biological studies to clarify the different control mechanisms regulating intracellular membrane trafficking. In addition we demonstrate peroxicretion of a diverse set of intracellular proteins. Therefore, we anticipate that the concept of peroxicretion may revolutionize the production of intracellular proteins from fungi and other microbial cells, as well as from mammalian cells.

Prevention of SIV Rectal Transmission and Priming of T Cell Responses in Macaques after Local Pre-exposure Application of Tenofovir Gel

Martin Cranage and colleagues find that topical tenofovir gel can protect against rectal challenge with SIV in a macaque model, and can permit the induction of SIV-specific T cell responses

Association of TLR7 Variants with AIDS-Like Disease and AIDS Vaccine Efficacy in Rhesus Macaques

In HIV infection, TLR7-triggered IFN-α production exerts a direct antiviral effect through the inhibition of viral replication, but may also be involved in immune pathogenesis leading to AIDS. TLR7 could also be an important mediator of vaccine efficacy. In this study, we analyzed polymorphisms in the X-linked TLR7 gene in the rhesus macaque model of AIDS. Upon resequencing of the TLR7 gene in 36 rhesus macaques of Indian origin, 12 polymorphic sites were detected. Next, we identified three tightly linked single nucleotide polymorphisms (SNP) as being associated with survival time. Genotyping of 119 untreated, simian immunodeficiency virus (SIV)-infected male rhesus macaques, including an ‘MHC adjusted’ subset, revealed that the three TLR7 SNPs are also significantly associated with set-point viral load. Surprisingly, this effect was not observed in 72 immunized SIV-infected male monkeys. We hypothesize (i) that SNP c.13G>A in the leader peptide is causative for the observed genotype-phenotype association and that (ii) the underlying mechanism is related to RNA secondary structure formation. Therefore, we investigated a fourth SNP (c.-17C>T), located 17 bp upstream of the ATG translation initiation codon, that is also potentially capable of influencing RNA structure. In c.13A carriers, neither set-point viral load nor survival time were related to the c.-17C>T genotype. In c.13G carriers, by contrast, the c.-17C allele was significantly associated with prolonged survival. Again, no such association was detected among immunized SIV-infected macaques. Our results highlight the dual role of TLR7 in immunodeficiency virus infection and vaccination and imply that it may be important to control human AIDS vaccine trials, not only for MHC genotype, but also for TLR7 genotype

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections.

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in 'natural host' species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.This work was supported by the Biotechnology and Biological Sciences Research Council and by the Wellcome Trust.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.ppat.100514

Datacenters as residual heat source for district heating in residential neighbourhoods of Amsterdam

The transformation of the residential heating system of Amsterdam into a sustainable heating system that no longer makes use of natural gas in 2050, of which 230.000 households will be heated with district heating, demands an exploration of sustainable local heat sources to use for district heating in Amsterdam. This aligns with the fundamentals of Urban Symbiosis and district heating where the conscious choice is made for the use of local heat sources and their by-products to serve as heat input for the district heating system when the heat source is in geographic proximity. Since a high amount of DC and production of residual heat output are present in Amsterdam, which are recommended as suitable heat sources for district heating but not yet investigated, the use of DC as sustainable local heat source is chosen in this thesis to explore as supplying heat source for district heating to fulfil the heat demand of residential neighbourhoods in Amsterdam. The research will search via a socio-technical perspective the technical feasibility of DC as heat source for district heating networks by estimating the extent of residual heat supply from the DC for residential neighbourhoods of Amsterdam. Furthermore, this thesis will search the social feasibility of the current institutional system of district heating with the addition of DC as heat supplying actor by mapping this as system configurations, since DC are not integrated yet in the district heating energy sector as heat supplying actor. The findings of this thesis will generate an insight of the elements of the current institutional system of district heating that facilitate or form a barrier for the integration of DC as heat supplying actor, while taking into consideration the technical feasibility of heat supply from DC for district heating.Joint Master of Science in Metropolitan Analysis, Design and Engineering at Delft University of Technology and Wageningen University & Research.Metropolitan Analysis, Design and Engineering (MADE