Biomedical subjects

Bent Aasted

Publications and source records attributed to Bent Aasted.

9 recordsLinked to original sources

PubMed2006

Cloning, characterization and mapping of porcine CD14 reveals a high conservation of mammalian CD14 structure, expression and locus organization.

The cell surface protein CD14 plays a central role in innate immunity as a pattern recognition receptor. CD14 is part of a receptor complex also including toll-like receptor 4 and MD2 proteins. Binding of the ligand lipopolysaccharide to the complex on myeloid cells leads to release of pro-inflammatory cytokines and mediators from the cell. In this study, we present the cloning, characterization and tissue expression pattern of a porcine CD14 encoding cDNA, and the chromosomal localization of the porcine CD14 gene. The open reading frame is predicted to encode a protein of 373 amino acids, which shows conservation of structural as well as functional regions when compared to other mammalian species. The CD14 gene was localized to porcine chromosome 2 in a region syntenic to human chromosome 5q. Transcription analysis shows that CD14 is widely expressed in tissues examined in this study, which correlates well with expression primarily on myeloid cells.

Amino Acid Sequence↗

PubMed2006

Cytokine mRNA profiles in pigs exposed prenatally and postnatally to Schistosoma japonicum.

The pig is a natural host for Schistosoma japonicum and a useful animal model of human infection. The aim of the present study was to assess the differences between the cytokine profiles in prenatally or postnatally S. japonicum exposed pigs. Seven prenatally exposed pigs, 7 postnatally exposed pigs and 4 uninfected control pigs were compared 27 weeks post exposure. Variables included worm burdens, tissue egg counts, liver pathology and mRNA levels of IL-2, IL-4, IL-10, IL-12, TNF-alpha, TGF-beta1 and IFN-gamma in the liver and the caecum, assessed by RT-PCR. Infection intensity and level of septal fibrosis were significantly higher in the postnatal group compared to the prenatal group (P < 0.05). A significant increase of IL-4 (P < 0.01), IL-10 (P < 0.01), IL-12 (P < 0.01) and TNF-alpha (P < 0.05) mRNA level was also observed in the caecum of prenatally infected animals compared to the control group (P < 0.01). The prenatal group showed higher levels of TGF-beta1 in the liver compared with the postnatally infected group (P< 0.05) and the control group (P< 0.01). This suppressive immune response correlated with previously reported low hepatic pathogenesis in prenatally exposed pigs.

Animals↗

PubMed2006

Various domains of the B-cell regulatory molecule CD72 has diverged at different rates in mammals: cloning, transcription and mapping of porcine CD72.

We report the cloning of the porcine B-cell co-receptor CD72, as well as genomic mapping and examination of transcription. The B-cell receptor (BCR) complex mediates signalling upon antigen recognition by the membrane bound BCR. Several co-receptors modulate this signal positively or negatively. CD72 has been shown to be a negatively regulating BCR co-receptor. We isolated and sequenced three porcine CD72 transcript variants. Using a pig radiation hybrid panel we found the porcine CD72 gene to be located on chromosome 1q21-28 in a region syntenic to human chromosome 9. The porcine CD72 gene is highly transcribed in lymph node, thymus and lung tissues as well as in pulmonary alveolar macrophages. The predicted porcine CD72 polypeptide shows conservation of immunoreceptor tyrosine-based inhibitory motifs and an extracellular C-type lectin domain. Compared to CD72 sequences from other mammals as well as from chicken, the polypeptide is highly conserved in the intracellular part and much less conserved in the extracellular part. We suggest that this difference might be due to the different nature of ligands and the constrains on these to co-evolve.

Alternative Splicing↗

PubMed2006

A time course study of immunological responses in Trichuris suis infected pigs demonstrates induction of a local type 2 response associated with worm burden.

In order to investigate immunological changes over time in pigs infected with Trichuris suis, we inoculated 40 pigs with 5000 infective T. suis eggs and left 40 pigs as uninfected controls. Equal numbers of pigs from both groups were sacrificed every other week from 1 to 11 weeks p.i. At necropsy tissue samples were collected from all pigs and their worm burdens were determined. In the proximal colon of T. suis-infected pigs infiltration of eosinophils peaked 5 weeks p.i. and mast cell infiltration developed from 5 to 11 weeks p.i. Histological evaluation of the proximal colon revealed that the presence of T. suis was closely associated with intestinal histopathological changes such as crypt hyperplasia, goblet cell hyperplasia and a general hypertrophy of mucosa. The crypt lengths were positively associated with worm burdens. Real-time PCR analysis of genes related to immune function indicate a local increased transcription of genes coding for CCR3, ARG1, MUC5AC, IL-4, IL-5, IL-13, FcepsilonR1alpha, and IL-13Ralpha2 and decreased expression of genes coding for iNOS, TNF-alpha, IL-10, CD3epsilon, CD80, CD86, IL-4Ralpha, IL-13Ralpha1 and CD40 in the proximal colon of pigs infected with T. suis. This local T-helper cell Type 2-like gene-expression pattern indicates that the Type 2 immune response characteristic of helminth infections in both mouse and humans also develops in pigs infected with T. suis. The results from this study expand our knowledge of the immunomodulatory effect of T. suis, a parasite that has proven effective in treating inflammatory bowel disease, when its eggs are administered regularly to patients.

Animals↗

PubMed2005

Summary of the animal homologue section of HLDA8.

Development of reagents against leukocyte differentiation antigens in veterinary immunology is slower compared to humans and mice. Cross-reactivity studies with monoclonal antibodies (mAb) generated against human molecules represent an excellent approach for the detection of new reagents for the minor characterised species. Three hundred seventy-seven commercially available mAb from different companies were tested for their reactivity with cells from 17 species--including non-human primates, ruminants, swine, horse, carnivores, rabbit, guinea pig, chicken and fish. In a first round of testing by flow cytometry (FCM) 182 mAb showed reactivity with atleast one of the species described above. Most of the cross-reactivity was found against non-human primate leukocytes, but also species in evolutionarily more distant from humans showed in some cases a clear staining pattern in flow cytometry (FCM). In a second round these FCM-results were confirmed by molecular analyses, by immunoprecipitation studies and analyses on transfectants. Interesting was the broad species-overlapping reactivity of mAb directed against CD9 (11 out of 17 species), CD11a (11/17), CD14 (11/17), CD18 (13/17), CD21 (7/17), CD29 (10/17), CD44 (13/17), CD45 (9/17), CD47 (10/17), and CD49d (13/17), CD61 (6/17), CD86 (7/17), CD91 (5/17), and CD172a (10/17), indicating evolutionary highly conserved epitopes on these surface molecules. Our results suggest the suitability of crossreactive mAb for the animal model studies. Moreover, these findings contribute to our understanding of the evolution of the immune system.

Animals↗

PubMed2005

CD molecules 2005: human cell differentiation molecules.

The immune system works through leukocytes interacting with each other, with other cells, with tissue matrices, with infectious agents, and with other antigens. These interactions are mediated by cell-surface glycoproteins and glycolipids. Antibodies against these leukocyte molecules have provided powerful tools for analysis of their structure, function, and distribution. Antibodies have been used widely in hematology, immunology, and pathology, and in research, diagnosis, and therapy. The associated CD nomenclature is commonly used when referring to leukocyte surface molecules and antibodies against them. It provides an essential classification for diagnostic and therapeutic purposes. The most recent (8th) Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), held in Adelaide, Australia, in December 2004, allocated 95 new CD designations and made radical changes to its aims and future operational strategy in order to maintain its relevance to modern human biology and clinical practice.

Antigens, CD↗

PubMed2005

DNA vaccination with the Aleutian mink disease virus NS1 gene confers partial protection against disease.

Aleutian disease virus (ADV) causes severe losses in mink. This happens in nature as well as in farms. In spite of several attempts to provide an efficient protective protein based vaccine, experiments have failed so far. Only partial protection has been obtained. The aim of this work was to construct and test a protective DNA vaccine based on the gene encoding for the ADV non-structural protein 1 (NS1) and to test this construct as a potential vaccine candidate against ADV infection or disease. First, the vaccine construct was tested by in vitro transfection studies. NS1 protein expression was found by immunofluorescent studies and the expected size of translated protein confirmed by Western blot. Then, 18 female mink were divided into three groups: a control group, a DNA vaccinated group, and a group which received DNA vaccine plus a boost with recombinant NS1 protein in the last immunization. After virus challenge, the two DNA vaccinated groups induced higher antibody levels in the first 23 weeks of the 32 week observation period. One month after virus challenge, the most interesting finding was, that the "DNA+protein" group exhibited a significantly higher percentage of CD8+ cells, when compared to the levels in the two other groups. This, we believe, indicate a memory CTL response created by the vaccination. Most CD8+ cells were found to contain interferon gamma as measured by FACS intracellular staining. Severity of Aleutian disease was judged by quantification of plasma gammaglobulin levels and mink death statistics. The findings let us to conclude, that the two DNA vaccinated groups of mink did show milder disease characteristics, but that the vaccine effect also in this trial could only be characterized as partial.

Aleutian Mink Disease↗

PubMed2004

Antibodies to Aleutian mink disease parvovirus in free-ranging European mink (Mustela lutreola) and other small carnivores from southwestern France.

Owing to the rapid decline of the European mink (Mustela lutreola) in France, a national conservation action plan has been initiated, in which scientific research to improve understanding of the causes of the decline is one of the primary objectives. In order to investigate the possible role of Aleutian disease parvovirus (ADV) in decline of the species, a serologic survey was conducted from March 1996 to March 2002 in 420 free-ranging individuals of six species of small carnivores distributed in eight departments of southwestern France. Antibodies to ADV were detected in 17 of 75 American mink (Mustela vison), 12 of 99 European mink, 16 of 145 polecats (Mustela putorius), four of 17 stone martens (Martes foina), one of 16 pine martens (Martes martes), and three of 68 common genets (Genetta genetta). Seroprevalence was significantly higher in American mink than in other species. Seropositive individuals with gamma globulin levels >20% were observed in four European mink, four American mink, two stone martens, and one pine marten. Geographic distribution of positive animals indicates the virus has spread to all areas where European mink are found. Furthermore, a trend of increasing prevalence seems to appear in Mustela sp. sympatric with American mink. Although further investigations are necessary to evaluate the role of ADV in decline of European mink, evidence of the virus in the wild at the levels found in our study has implications for conservation of this species.

Aleutian Mink Disease↗

PubMed2003

The resistance of delayed xenograft rejection to alpha(1,3)-galactosyltransferase gene inactivation and CD4 depletion in a mouse-to-rat model.

Critical to the prevention of xenograft loss is the prevention of delayed xenograft rejection (DXR), due to its resistance to conventional immunosuppression. The role of the carbohydrate galactose-alpha1,3-galactose (alpha1,3Gal) has been a matter of great debate and it has been proposed that the reaction between alpha1,3Gal epitopes on donor endothelial cells and recipient anti-alpha1,3Gal antibodies (Abs) may damage the graft during DXR. Recipient anti-alpha1,3Gal Abs are produced by CD4-dependent B cells. To test the above-mentioned hypothesis, hearts from alpha1,3Gal-free mice (GT-Ko mice), generated by alpha1,3-galacto-syltransferase gene disruption, were transplanted to anti-alpha1,3Gal antibody-free Lew/Mol rats. This model consists of an alpha1,3Gal/alpha1,3Gal-antibody-free environment, eliminating a possible influence of this specific system on DXR. A subgroup of recipients were furthermore CD4 depleted in order to inhibit CD4-dependent B-cell antibody production. Rejected hearts were evaluated by light- and immunofluorescence microscopy. Treatment effects on recipient T-cell subsets and cytokine expression were analyzed by flow cytometry, while antibody production was measured by ELISA. All recipients developed DXR with no differences among the groups. DXR was related to thrombosis with IgG and IgM desposition in vessel walls, as well as macrophage and granulocyte accumulation in the myocardium. No complement C3, CD4 cells or NK cells were found. Flow cytometric analysis confirmed peripheral blood CD4 depletion and IFN-gamma suppression in CD4 Ab-treated recipients. Finally, ELISA showed that specific anti-alpha1,3Gal Ab production was absent. However, Ab(s) against an unidentified Galalpha 1 were found among recipients. In our model, DXR is resistant to alpha1,3-galactosyltransferase gene inactivation and CD4 depletion. However, other Galalpha 1 epitopes and antibodies may play a role during DXR. Further studies are needed to elucidate the precise pathways leading to DXR.

Animals↗