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C Fossum

Publications and source records attributed to C Fossum.

58 records · Page 4Linked to original sources
PubMed1985

Evaluation of flow cytometry and fluorescence microscopy for the estimation of bovine mononuclear phagocytes.

Bovine blood mononuclear cells were isolated by density gradient centrifugation on Ficoll-Paque. Phagocytic mononuclear cells were characterized functionally by ingestion of fluorescent latex beads. After incubation with beads the cells were treated with Triton X-100 and propidium iodide (PI) to stain DNA. Cells were analyzed with a FACS-III instrument connected to a Nuclear Data-6660 multiparameter computer system. The computer was used to evaluate the 2 parameter histograms in order to enumerate the percentage of cells with different numbers of associated beads. With this system we also obtained information about cell concentration and number of beads per cell. Results from flow cytometry and manual counting by fluorescence microscopy were compared and good correlation (r = 0.91) was obtained. During the first hours of incubation latex beads adhered to cell surfaces as demonstrated by FCM histograms and fluorescence microscopy. Blood mononuclear phagocytes have to be incubated for several hours before significant phagocytotic activity can be detected.

Animals↗
PubMed1985

Suppressor activity of bovine Fc gamma positive cells during a persistent infection with Mycobacterium avium.

The cell mediated immune response (CMI) was measured in calves after experimental infection with Mycobacterium avium. Using the tuberculin skin test a CMI response could be measured from four to 14 weeks after infection, and with a lymphocyte stimulation (LS) test from six to 40 weeks. One year after infection no CMI response was detected by either of the tests, in spite of the fact that in such calves M avium bacteria could be found in the intestinal lymph nodes at autopsy. After removal of mononuclear cells bearing receptors for the Fc part of IgG, the peripheral blood lymphocytes obtained from a calf infected one year earlier responded to M avium pure protein derivative in the LS test in contrast to lymphocytes obtained from uninfected calves.

Animals↗
PubMed1982

Salmonella typhimurium infection in calves: specific immune reactivity against O-antigenic polysaccharide detectable in in vitro assays.

Peripheral blood lymphocytes collected from calves infected experimentally with Salmonella typhimurium (O antigens 4,5,12) or Salmonella sp. serotype dublin (O 9,12) were stimulated with various bacterial cell envelope components, and their [3H]thymidine incorporation was measured. It was found that peripheral blood lymphocytes from infected calves incorporated significantly more [3H]thymidine than peripheral blood lymphocytes from uninfected controls (P values ranged from less than 0.05 to less than 0.0005). The responder cell type was found in a B-cell-depleted and T-cell-enriched population. The Salmonella infections elicited T-cell responses against at least two cell envelope components: (i) a specific response against the O-antigenic polysaccharide chain of the lipopolysaccharide (This was evident in that a polysaccharide from S. enteritidis [O 9,12] which shares a trisaccharide structure [O antigen 12 determinant] with S. typhimurium stimulated [3H]thymidine uptake, which, although lower than in the homologous system, was significantly higher than that seen after incubation with unrelated Salmonella sp serotype thompson polysaccharide.) and (ii) a response against outer membrane proteins (porins), which are present in both S. typhimurium and Salmonella sp. serotype dublin. The experiments with peripheral blood lymphocytes from Salmonella sp. serotype dublin-infected calves gave results in excellent agreement with those obtained in S. typhimurium-infected calves.

Animals↗