• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.51-66
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• 2007

The purpose of this study was to evaluate the effect of a subsequent infection of porcine reproductive and respiratory syndrome(PRRS) virus to pigs with A pleuropneumonia. Twenty three 7-week-old commercial pigs were infected intratracheally with PRRS virus and/or A pleuropneumoniae serotype 5. Serum antibody titers were examined by an enzyme-linked immunosorbent assay(ELISA) and proportion of porcine leukocyte subpopulations in peripheral blood was examined by flow cytometry. In this experiment, antibodies against PRRS virus and A pleuropneumoniae were detected at 2 weeks and 1 week postinfection and the number of antibody positive pigs were gradually increased. And in proportion to leukocyte subpopulations in peripheral blood of pigs infected with A pleuropneumoniae compared with pigs administrated with saline, the proportion of PoCD4 and N cells were increased(P<0.1). Furthermore, in proportion to leukocyte subpopulations in peripheral blood of pigs infected with PRRS virus followed by A pleuropneumoniae compared with pigs administrated with saline, the proportion of MHC class II, PoCD4 and B cells were significantly increased(P<0.1). The results indicated that dual infection with PRRS virus and A pleuropneumoniae induced the stronger immune responses associated with macrophages and Th cells in pigs than single infection with PRRS virus or A pleuropneumoniae.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.275-286
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• 1994

Plasma protein which has been known as one of nonspecific immunostimulators was added to feedstuff to examine its effect on the enhancement of cellular immune response in porcine immune system. A total of 40 piglets, 20 male and 20 female each, were fed for 30 days with or without plasma protein. The peripheral blood were collected and analyzed for the investigation of leukocyte subpopulations and their activities by using a panel of monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry. The results obtained as follows. 1. Total weight gain, daily feed intake and feed conversion rate for 10 days were significantly improved to 56%, 20% and 22% in the piglets fed plasma protein, respectively. 2. A significant increase in N (null or non T/non B) cells was also noticed. Leukocyte proportion from piglets fed plasma protein was 20.2-24.7%, otherwise that from piglets fed without plasma protein was 12.3-13.4%, respectively. 3. A significant increase in the proportion of B cells and cells expressing poCD1 was not found in piglets fed plasma protein. 4. Reaction with monoclonal antibodies specific to adhesion molecules, poCD11a, poCD11b, poCD44 and poCD45A and poCD45B, has shown that leukocyte subpopulation from piglets fed plasma protein did not significantly higher than that from piglets fed without plasma protein. 5. Total proportion of granulocytes and monocytes was about 50% in both group and the proportion after treated with Hypaque/Ficoll was 2.7% and 5.8% in each group, respectively.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.287-299
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• 1994

Plasma protein which has been known as one of nonspecific immunostimulators was added to feedstuff to examine its effect on the enhancement of cellular immune response in porcine immune system. A total of 40 piglets, 20 male and 20 female each, were fed for 30 days with or without plasma protein. The peripheral blood were collected and analyzed for the investigation of leukocyte subpopulations and their activities by using a panel of monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry. The results obtained as follows. 1. Subpopulations expressing major histocompatibility complex(MHC) class I antigen were $96.2{\pm}3.1%$ and $86.6{\pm}3.8%$ in piglets fed with plasma protein and in piglets fed without plasma protein, respectively. 2. Proportion of leukocyte subpopulation expressing MHC class II antigens were significantly higher in the piglets fed with plasma protein than ones without plasma protein. The proportion was $27.6{\pm}3.6%$ and $16.6{\pm}2.2%$ in MHC class II DQ antigen, and $28.1{\pm}2.0%$ and $20.0{\pm}0.3%$ in MHC class II DR antigen, respectively. 3. A significant increase in the proportion of cells expressing poCD2 was not found in piglets fed plasma protein. 4. Proportion of subpopulation expressed porcine(Po) CD4 antigens which specific to helper T lymphocytes were not increased (18.3-19.1% vs. 25.6-28.8%), rather slightly decreased, in plasma protein-treated group. 5. The most important increase of proportion in plasma protein-treated group was the leukocyte subpopulation specific to $poCD8^+$ T cytotoxic/suppressor lymphocytes. The expression level was significantly higher up to 45.9-47.1% in plasma protein-treated group in comparing with 29.7-33.0% in non-plasma protein-treated group. 6. Lymphoblastogenetic responses using different concentrations of Con A mitogen and plasma protein has found that the responses of lymphocyte from piglets fed plasma protein was significantly activated (p<0.01). The activities measured by 3[H]-thymidine incorporation showed 3-6 times stronger in plasma protein-treated group than those in non-plasma protein-treated group. The study has concluded that plasma protein, which has known as a nonspecific immunostimulator, may have an immunoenhancing activities in porcine lymphoid system by increase the activated cell proportions and their blastogenetic properties which is critical to host immune responses.