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Abstract: Three hundred and seventy six monoclonal antibodies (mAbs) raised against human leukocyte surface antigens were analyzed by flow cytometry for cross reactivities against mink leukocytes. We found 53 mAbs (14%) to cross react. This study defined cross reactions to the following human markers: CD1a, CD9 (4 mAbs), CD10, CD11a (2 mAbs), CD14 (3 mAbs), CD18 (5 mAbs), CD20 (atypical reaction), CD21, CD25 (atypical reaction), CD29 (3 mAbs), CD32, CD41, CD42a, CD44 (4 mAbs), CD45, CD45RO, CD47 (2 mAbs), CD49d (3 mAbs), CD61 (2 mAbs), CD62P, CD66abcd, CD71, CD75s, CD79b (2 mAbs), CD86, CD88, CD104 (atypical reaction), CD172a, CD236R (glycophorin C, (atypical reaction)), Xg(a) carbohydrate antigen, Rhesus antigen and two unspecified PAN-reactive mAbs. In order to characterize the molecular mass of the corresponding cross reacting mink markers, the mAbs were used to immunoprecipitate the surface antigens. Fourteen mAbs out of the 53 mAbs reactive with mink leukocytes gave reproducible IP findings. The masses of the precipitated antigens were generally in good agreement with those of the homologous human markers. We also performed immunohistochemical staining analyses on formalin fixed, paraffin embedded mink tissue from lymph node and spleen, and found 7 out of 22 mAbs to give a positive signal. Generally, the immunohistological analyses resulted in expected staining patterns. [Copyright &y& Elsevier]

Abstract: Glycans terminating in sialic acids serve as receptors for influenza viruses. In this study ferrets were infected with influenza virus A/New Caledonia/20/99, and the in situ localization of sialic acids linked α2-3 and α2-6 in the airways was investigated in infected and non-infected animals by use of sialic acid detecting lectins and a monoclonal antibody towards the Sialyl-Tn antigen. The goblet cells in the bronchi from non-infected ferrets expressed Sialylα2-6Gal glycans, while the seromucinous glands in the submucosa expressed Sialylα2-3Gal glycans. In the infected animals, the surface epithelial cells in some bronchi showed metaplasia and expressed the Sialyl-Tn antigen: Sialylα2-6GalNAc-O-Thr/Ser. The submucosal tracheal glands in these animals showed increased expression of both Sialylα2-3 and Sialylα2-6 epitopes. [Copyright &y& Elsevier]

The aim of the study was to investigate lipopolysaccharide (LPS)-induced short and long term changes in capacity for intracellular cytokine-production of bovine circulating peripheral blood mononuclear cells (PBMCs). Eight dairy cows each received three intravenous injections of Escherichia coli LPS (10, 100 and 1000 ng/kg, consecutively) at 3 week intervals. Intracellular cytokine production was determined by flow cytometry in PBMCs obtained 0, 2, 6 and 24 h after each LPS challenge. After LPS administration, proportions of monocytes producing tumour necrosis factor (TNF)α, interleukin (IL)-11β and IL-8, as well as proportions of circulating lymphocytes producing interferon (IFN) γ, decreased significantly. Within 24 h, proportions had returned to or increased above pre-injection levels. Proportions of lymphocytes producing IL-4 and IL-10 increased significantly after injection of 1000 ng LPS/kg. This study demonstrated that cytokine profiles shift quickly, but temporarily, to favour the anti-inflammatory response immediately after LPS exposure. The long term response to LPS Was opposite to the immediate response, as cytokine profiles shifted in the 3 weeks between challenges towards a pro-inflammatory response. Proportions of monocytes producing IL-1β and TNFα determined immediately before the second and/or third LPS injection were higher than proportions determined before the first injection, whereas pre-injection proportions of lymphocytes producing IL-4 decreased with each challenge. These changes may result in a quicker host response to invading pathogens. [ABSTRACT FROM AUTHOR]

Abstract: Swine workshop cluster 9 (SWC9) antibody identifying a porcine epitope on macrophages and thymocytes was used to precipitate and characterize the molecule from biotinylated macrophages and to obtain peptide sequence by mass spectrometry. The protein was identified as ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1/CD203a). The porcine NPP1/CD203a encoding gene was mapped to chromosome 1 using a radiation hybrid panel, and transcription was investigated by RT-PCR analysis of several tissues. The cDNA was cloned and introduced into COS7 cells resulting in expression of functionally active enzyme and verification of the specificity of an SWC9 reacting monoclonal antibody. The antibody was used for immunohistochemical examination of various porcine tissues. Most prominent expression of NPP1/CD203a was found in lung macrophages and liver sinusoids. [Copyright &y& Elsevier]

Abstract: Concomitant infections with helminths and bacteria may affect the course and the resulting disease outcome of the individual infections. Salmonella, Oesophagostomum, Trichuris and Ascaris coexist naturally in pig herds in Denmark, and possible interactions were studied. Pigs in one experiment were trickle infected with low or moderate dose levels of Oesophagostomum spp. and challenge infected with S. Typhimurium. In another experiment, pigs were inoculated with S. Typhimurium followed by a challenge exposure to either Oesophagostomum, Trichuris or Ascaris. Enhancement of the Salmonella infection was not demonstrated in either experiment. The helminth effect on the pigs was modest and may explain the lack of influence on the Salmonella infection. A previous experiment with a larger Oesophagostomum infection level resulted in enhancement of the S. Typhimurium infection. A dose dependency of the interaction is therefore suggested. However, the relatively high worm burdens in the present study suggest that infection with these common pig helminths does generally not influence the course of concurrent S. Typhimurium infections under natural conditions. [Copyright &y& Elsevier]

It is well known that piglets congenitally infected with porcine reproductive and respiratory syndrome virus (PRRSV) can be viremic at birth, and that preweaning mortality due to secondary infections often increases during acute outbreaks of PRRS. Therefore, an immunosuppressive effect of in utero infection has been suggested. The aim of the present study was to characterise the changes of leukocyte populations in piglets surviving in utero infection with PRRSV. A total of 27 liveborn uninfected control piglets and 22 piglets infected transplacentally with a Danish strain of PRRSV were included. At 2 and 4 weeks of age, 21 of 22 (96%) and 7 of 14 (50%) examined infected piglets were still viremic, whereas PRRSV could not be detected in the six infected piglets examined at 6 weeks of age. Flow cytometry analysis was used to determine the phenotypic composition of leukocytes in peripheral blood and bronchoalveolar lavage fluid (BALF) of 2-, 4- and 6-week-old infected piglets and age-matched uninfected controls. The key observation in the present study is that high levels of CD8+ cells constitute a dominant feature in peripheral blood and BALF of piglets surviving in utero infection with PRRSV. In BALF, the average high level of CD8+ cells in 2-week-old infected piglets (33.4±12.6%) was followed by a decline to 7.3±3.0 and 11.1±3.0% at 4 and 6 weeks of age. BALF of control piglets contained 1.6±0.9, 2.3±1.8 and 1.9±0.5% CD8+ cells, only. In peripheral blood, however, the average number of CD8+ cells remained at high levels in the infected piglets throughout the post-natal experimental period (2.8±1.9, 2.9±1.8 and 3.2±1.7×106 CD8+ cells/ml at 2, 4 and 6 weeks, respectively). In the controls, the average levels of CD8+ cells were 0.9±0.2, 1.9±1.7 and 1.6±0.5×106/ml, respectively. Furthermore, the numbers of CD2+, CD4+CD8+ and SLA-classII+ cells, respectively, in peripheral blood, together with the levels of CD2+ and CD3+ cells in BALF were increased in the infected piglets infected in utero compared to the uninfected controls.The kinetic analyses carried out in the present study reflect that in utero infection with PRRSV modulates immune cell populations in peripheral blood and BALF of surviving piglets. The observed changes are characterised by high levels of CD8+ cells supporting an important role of these cells in PRRSV infection. The present results, however, do not support the existence of post-natal immunosuppression following in utero infection with PRRSV. [Copyright &y& Elsevier]

Eleven monoclonal antibodies specific for ovine, bovine and human cytokines were investigated by flow cytometry for cross-reactivities with cytokines produced by peripheral blood mononuclear cells (PBMCs) from sheep, cattle, goat, swine, horse, dog, mink, rabbit and human. Four antibodies specific for IL-4, IL-8, IFN-γ and TNF-α cross-reacted with cytokines from a majority of the species investigated. These antibodies can be applied to flow cytometric studies of cytokine production by PBMCs from several veterinary species. Another five antibodies specific for IL-2, IL-6, GM-CSF and IFN-γ (two antibodies) cross-reacted weakly and with a variable number of animal species. These antibodies could in certain situations be useful in flow cytometry. In a number of cases the immunological cross-reactivities were confirmed by Western blot analyses. Overall, the results of this study will remedy some of the lack of species-specific anti-cytokine antibodies in veterinary research. [Copyright &y& Elsevier]