http://repub.eur.nl/res/aut/15728/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/34649/ 2011-10-25T00:00:00Z Currently, there is no animal model known that mimics natural nasal colonization by Staphylococcus aureus in humans. We investigated whether rhesus macaques are natural nasal carriers of S. aureus. Nasal swabs were taken from 731 macaques. S. aureus isolates were typed by pulsed-field gel electrophoresis (PFGE), spa repeat sequencing and multi-locus sequence typing (MLST), and compared with human strains. Furthermore, the isolates were characterized by several PCRs. Thirty-nine percent of 731 macaques were positive for S. aureus. In general, the macaque S. aureus isolates differed from human strains as they formed separate PFGE clusters, 50% of the isolates were untypeable by agr genotyping, 17 new spa types were identified, which all belonged to new sequence types (STs). Furthermore, 66% of macaque isolates were negative for all superantigen genes. To determine S. aureus nasal colonization, three nasal swabs from 48 duo-housed macaques were taken during a 5 month period. In addition, sera were analyzed for immunoglobulin G and A levels directed against 40 staphylococcal proteins using a bead-based flow cytometry technique. Nineteen percent of the animals were negative for S. aureus, and 17% were three times positive. S. aureus strains were easily exchanged between macaques. The antibody response was less pronounced in macaques compared to humans, and nasal carrier status was not associated with differences in serum anti-staphylococcal antibody levels. In conclusion, rhesus macaques are natural hosts of S. aureus, carrying host-specific lineages. Our data indicate that rhesus macaques are useful as an autologous model for studying S. aureus nasal colonization and infection prevention. http://repub.eur.nl/res/pub/28652/ 2010-11-30T00:00:00Z The complete nucleotide sequences of three chimpanzee polyomavirus genetic variants were determined. Phylogenetic analysis indicated that the viruses form two different genotypes of ChPyV. Comparison with other primate polyomaviruses revealed a putative agnogene, and an unusually long VP1 open reading frame. The transcriptional control regions (TCR) of the viruses were extremely short (155 nucleotides), and highly conserved amongst the genotypes. Analysis of the TCR from different chimpanzee subspecies, and from a series of tissues from five individuals confirmed its genetic stability, and also indicates that double-infections with different genotypes can occur. http://repub.eur.nl/res/pub/25593/ 2010-10-26T00:00:00Z Introduction: There is an ever-increasing need for animal models to evaluate efficacy and safety of new therapeutics in the field of rheumatoid arthritis (RA). Particularly for the early preclinical evaluation of human-specific biologicals targeting the progressive phase of the disease, there is a need for relevant animal models. In response to this requirement we set out to develop a model of collagen-induced arthritis (CIA) in a small-sized nonhuman primate species (300 to 400 g at adult age); that is, the common marmoset (Callithrix jacchus).Methods: Twenty-two animals divided into three experiments were immunized with collagen type II (CII) of either bovine or chicken origin with different immunization strategies. The animals were analyzed for clinical manifestation of arthritis, hematology and clinical chemistry, immunological responses against CII and histopathological features of the arthritis.Results: Clinically manifest arthritis was observed in almost 100% (21 out of 22) of the animals. Fifty percent of the animals developed semi-acute CIA while the other 50% displayed a more chronic disease. Both cellular (CD3/CD4 and CD3/CD8) and humoral responses (IgM and IgG) against CII were involved in the development of the disease. Besides mild histopathological changes in bone and cartilage, severe inflammation in extraarticular tissues like periosteum and subcutaneous tissues was observed.Conclusions: This new model in marmosets more closely resembles chronic RA with respect to the chronic disease course and pathomorphological presentation than the more acute monophasic and destructive CIA model in macaques. This model can therefore fill a niche in preclinical testing of new human specific therapeutics. http://repub.eur.nl/res/pub/19634/ 2010-06-01T00:00:00Z The marked improvement of several immune-mediated inflammatory diseases during pregnancy has drawn attention to pregnancy hormones as potential therapeutics for such disorders. Low molecular weight fractions derived from the pregnancy hormone human chorionic gonadotrophin (hCG) have remarkable potent immunosuppressive effects in mouse models of diabetes and septic shock. Based on these data we have designed a set of oligopeptides related to the primary structure of hCG and tested these in models of septic shock in mice and rhesus monkeys. We demonstrate that mice exposed to lipopolysaccharide (LPS) and treated subsequently with selected tri-, tetra-, penta- and hepta-meric oligopeptides (i.e. MTR, VVC, MTRV, LQGV, AQGV, VLPALP, VLPALPQ) are protected against fatal LPS-induced septic shock. Moreover, administration of a cocktail of three selected oligopeptides (LQGV, AQGV and VLPALP) improved the pathological features markedly and nearly improved haemodynamic parameters associated with intravenous Escherichia coli-induced septic shock in rhesus monkeys. These data indicate that the designed hCG-related oligopeptides may present a potential treatment for the initial hyperdynamic phase of septic shock in humans. http://repub.eur.nl/res/pub/25447/ 2009-06-15T00:00:00Z Microglia activation is a prominent feature in many neuroinflammatory disorders. Unrestrained activation can generate a chronic inflammatory environment that might lead to neurodegeneration and autoimmunity. Extracellular adenosine modulates cellular activation through adenosine receptor (ADORA)-mediated signaling. There are four ADORA subtypes that can either increase (A2Aand A2Breceptors) or decrease (A1and A3receptors) intracellular cyclic AMP levels. The expression pattern of the subtypes thus orchestrates the cellular response to extracellular adenosine. We have investigated the expression of ADORA subtypes in unstimulated and TLR-activated primary rhesus monkey microglia. Activation induced an up-regulation of A2Aand a down-regulation of A3receptor (A3R) levels. The altered ADORA-expression pattern sensitized microglia to A2Areceptor (A2AR)- mediated inhibition of subsequent TLR-induced cytokine responses. By using combinations of subtype-specific agonists and antagonists, we revealed that in unstimulated microglia, A2AR-mediated inhibitory signaling was effectively counteracted by A3R-mediated signaling. In activated microglia, the decrease in A3R-mediated signaling sensitized them to A2AR-mediated inhibitory signaling. We report a differential, activation state-specific expression of ADORA in microglia and uncover a role for A3R as dynamically regulated suppressors of A2AR- mediated inhibition of TLR-induced responses. This would suggest exploration of combinations of A2AR agonists and A3R antagonists to dampen microglial activation during chronic neuroinflammatory conditions. Copyright http://repub.eur.nl/res/pub/36236/ 2007-11-15T00:00:00Z Activated microglia are found in a variety of neuroinflammatory disorders where they have attributed roles as effector as well as antigen-presenting cells (APC). Critical determinants for the multifaceted role of microglia are the differentiation potential of microglia and their mode of activation. In this study, we have investigated the effects of M-CSF and GM-CSF-mediated differentiation of adult primate microglia on their cellular phenotype, antigen presentation, and phagocytic function as well as on Toll-like receptor (TLR)-mediated responses. We show that although cell morphology and expression levels of activation markers were markedly different, differentiation with either factor yielded microglia that phenotypically and functionally resemble macrophages. Both M-CSF and GM-CSF-differentiated microglia were responsive to TLR1/2, 2, 3, 4, 5, 6/2, and 8-mediated activation, but not to TLR7 or 9-mediated activation. Intriguingly, M-CSF-differentiated microglia expressed higher levels of TLR8-encoding mRNA and protein, and produced larger amounts of proinflammatory cytokines in response to TLR8-mediated activation as compared to GM-CSF-differentiated microglia. While differentiation of adult microglia by growth factors that can be produced endogenously in the central nervous system is thus unlikely to change their APC function, it can alter their innate responses to infectious stimuli such as ssRNA viruses. Resident primate microglia may thereby help shape rather than initiate adaptive immune responses. http://repub.eur.nl/res/pub/37081/ 2007-10-01T00:00:00Z The identification of FOXP3 expressing cells in recipients of an allograft, in particular inside the graft itself, may help to define criteria for immunosuppressive drug withdrawal. We therefore examined expression patterns of several regulatory T-cell (Treg) markers in kidney biopsies and kidney tissues taken at the time of graft rejection from monkeys treated with αCD40, αCD86, CsA, a combination of these or after drug withdrawal. In advanced stages of rejection, organized multifocal nodular infiltrates, with mature dendritic cells, T cells and B cells could be found. In contrast, interstitial infiltrates contain more macrophages, less T cells and few B cells. Cells expressing FOXP3, CD25 and CTLA-4 were mainly found in nodular infiltrates of rejected tissue samples. A significant correlation was found between the percentage FOXP3+cells and markers for rejection, i.e. creatinine levels and Banff interstitial and tubular infiltrate scores. The type of immunosuppression did not influence the percentage of cells expressing Treg markers. Three animals with prolonged drug-free survival showed low numbers of FOXP3+cells. We conclude that the presence of intragraft FOXP3+cells is not confined to tolerated grafts, but should be considered as part of the normal immune response during rejection. http://repub.eur.nl/res/pub/13812/ 2005-06-01T00:00:00Z The use of classical smallpox vaccines based on vaccinia virus (VV) is associated with severe complications in both naive and immune individuals. Modified vaccinia virus Ankara (MVA), a highly attenuated replication-deficient strain of VV, has been proven to be safe in humans and immunocompromised animals, and its efficacy against smallpox is currently being addressed. Here we directly compare the efficacies of MVA alone and in combination with classical VV-based vaccines in a cynomolgus macaque monkeypox model. The MVA-based smallpox vaccine protected macaques against a lethal respiratory challenge with monkeypox virus and is therefore an important candidate for the protection of humans against smallpox.