• Korean Journal of Veterinary Research
• /
• v.45 no.2
• /
• pp.185-189
• /
• 2005

Actinobacillus pleuropneumoniae is the causative agent of a porcine contagious pleuropneumonia. Among several virulence factors including exotoxin (Apx toxins), LPS, transferrin-binding proteins, OMPs, and some proteases, Apx toxins have been major targets for the protection study. In this study, cloning and expression of A. pleuropneumoniae Apx I and Apx II toxin, which are produced by all highly virulent strains, were performed by Escherichia coli expression system. Genes coding Apx I and II toxin were amplified from the A. pleuropneumoniae serotype 5 genomic DNA using polymerase chain reaction and cloned to a prokaryotic expression vector, pRSET. Expression of the Apx I and Apx II coding sequences in E. coli resulted in the formation of insoluble inclusion bodies purified according to a denaturing purification protocol, which employs the use of guanidium. Recombinant proteins were purified using $Ni^{2+}$-charged resin affinity purification. This expression and purification system made it possible to produce Apx I and Apx II in large amounts for further immunologic studies.

• Korean Journal of Veterinary Service
• /
• v.42 no.4
• /
• pp.201-216
• /
• 2019

Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failure in sows and respiratory distress in all age pigs. Porcine respiratory disease complex (PRDC) is a disease caused by opportunistic bacterial infection secondary to a weakened immune system by a preceding respiratory infection. In this study, we tried to compare the immune responses in PRRS and PRDC groups to clearly characterize the disease severity. Eighty-five pigs were infected with various Korean field PRRS virus strains. Infected animals were classified into PRRS (n=32) and PRDC (n=53) groups based on lung lesions such as interstitial pneumonia, suppurative pneumonia, and pleuropneumonia. The immune cell population of bronchoalveolar lavage cells (BALc) was evaluated on 14 and 28 days post infection (dpi) and PMBC cytokine expression was measured on 0, 3, 7, 14 dpi to investigate early inflammatory reactions. Pulmonary lesion severity was negatively correlated with alveolar macrophage (AM) in both PRRS and PRDC groups on 14 and 28 dpi. AM in BALc was less populated in PRDC group on 28 dpi compared to PRRS group. AM in BALc was significantly less populated in PRDC group on 28 dpi compared to 14 dpi. In addition, cytotoxic T lymphocyte (CTL) in BALc was higher populated in PRDC group on 14 dpi and 28 dpi compared to PRRS group. In the case of PBMC cytokine TNF-α, IFN-α, IL-1β, IFN-γ, FoxP3, and IL-2, the PRRS group showed higher expression than the PRDC group on 7 dpi, 14 dpi, 7 dpi, 14 dpi, 14 dpi, and 14 dpi, respectively. On the other hand, in the case of IFN-β, IL-6, IL-8, IL-4, and IL-17, the PRDC group showed higher PBMC cytokine expression at 14 dpi, 7 dpi, 14 dpi, 3 dpi, and 3 dpi, respectively, than the PRRS group. Based on these results, our study could characterize differential immune responses in pigs with PRRS or PRDC.

• Korean Journal of Veterinary Research
• /
• v.42 no.3
• /
• pp.371-376
• /
• 2002

Swine respiratory diseases have induced severe economic lasses in swine industry worldwide. Therefore, several methods have been made and applied to prevent and control the diseases. However, these methods still have a problem and also induce side effects. Recently, the use of egg yolk antibody was introduced to control and prevent the diseases as one of new trials. As a study of using egg yolk antibody, antibody titers against several different antigens of major pathogens in swine respiratory diseases were compared in egg yolk and serum of hens immunized with those antigens. The titers were measured by ELISA using the antigens as coating antigens. The relationship in antibody titers between egg yolk and serum were identified by analysis of variance for linear regression. Almost of antigens used in this study showed the high relationship in antibody titers between egg yolk and serum (r = 0.87 ~ 0.93) even though the relationship in antibody titers against P. multocida A:3 IROMP was slightly low (r = 0.74)(P<0.01). These results indicated that antibody titer in egg yolk could be useful to predict the titer in serum of chicken.

• Journal of Veterinary Clinics
• /
• v.9 no.2
• /
• pp.401-406
• /
• 1992

For the purpose of effective treatment and prevention of porcine respiratory diseases, Enrofloxacin(Baytril premix) was administered in the feed to trial herd occurred sporadically the respiratory diseases and then a serious investigation was carried out on the therapeutic effect, weight gain, feed conversion rate and lung lesion scoring. The results obtained were as follows, 1. The grower pigs which were administered with Baytril premix for 10 days gained the average body weight of 31kg for 33 days compared to 20.5kg of control group(p<0.05). Also drastical improvement of feed conversion rate(p<0.05) and disappearance of clinical signs were approved. 2. Average scorings of lung lesions were 7.92% in the medication group and 15.8% in the control group respectively. 3. Respiratory diseases outbreaked in the trial farm were pleuropneumonia caused by Actinobacillus (Haemophilus)pleuropneumoniae, Mycoplasmal pneumonia and Pasteurellosis.

• Food Science and Biotechnology
• /
• v.27 no.6
• /
• pp.1823-1831
• /
• 2018

This study examined the efficacy of Atractylodes macrocephala Koidz (AMK) protein and polysaccharide extracts as adjuvant or adjuvant booster when given together with porcine pleuropneumonia vaccine. Experimental mice (n = 5/group) were subcutaneously immunized with $25{\mu}g$ ApxIIA #3 antigen, a target protein against A. pleuropneumoniae, together with alum and/or various concentrations ($0-500{\mu}g$) of the AMK extracts, while the control group received PBS only. Immunization with ApxIIA #3 antigen increased the antigen-specific IgG titer and this increase was enhanced in the immunization together with AMK protein, but not polysaccharide extract. Supplementation of AMK protein extract exhibited dose-dependent increases in the antigen-induced protective immunity against A. pleuropneumoniae challenge and in the lymphocyte proliferation specific to the antigen. Glycoproteins present in the AMK extract were the active components responsible for immune response induction. Collectively, the present findings suggest that AMK glycoproteins are useful as immune stimulating adjuvant or adjuvant booster.

• Journal of Veterinary Science
• /
• v.21 no.2
• /
• pp.20.1-20.13
• /
• 2020

Actinobacillus pleuropneumoniae (APP) causes a form of porcine pleuropneumonia that leads to significant economic losses in the swine industry worldwide. The apxIBD gene is responsible for the secretion of the ApxI and ApxII toxins and the pnp gene is responsible for the adaptation of bacteria to cold temperature and a virulence factor. The apxIBD and pnp genes were deleted successfully from APP serotype 1 and 5 by transconjugation and sucrose counter-selection. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants lost hemolytic activity and could not secrete ApxI and ApxII toxins outside the bacteria because both mutants lost the ApxI- and ApxII-secreting proteins by deletion of the apxIBD gene. Besides, the growth of these mutants was defective at low temperatures resulting from the deletion of pnp. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants were significantly attenuated compared with wild-type ones. However, mice vaccinated intraperitoneally with APP5ΔapxIBDΔpnp did not provide any protection when challenged with a 10-times 50% lethal dose of virulent homologous (APP5) and heterologous (APP1) bacterial strains, while mice vaccinated with APP1ΔapxIBDΔpnp offered 75% protection against a homologous challenge. The ΔapxIBDΔpnp mutants were significantly attenuated and gave different protection rate against homologous virulent wild-type APP challenging.

• Korean Journal of Veterinary Research
• /
• v.40 no.1
• /
• pp.173-186
• /
• 2000

This experiment was carried out to investigate the tendency of incident diseases in pre- and post- weaning piglets which ages were 1 to 7 weeks old by laboratory diagnosis and in order to minimize death in preweaning piglets and of stunted growth in postweaning piglets. The result of this experiment used as the basic data for the preventive programs in pre- and post- weaning piglets and were as follows: 23 different diseases diagnosed in 331 cases were studied in relation to age, season, and etiology. The most prevelent diseases of pre- and post- weaning piglet were Colibacillosis(79 case, 23.9%) and the major diseases were Salmonellosis(44 cases, 13.3%), Anemia(37 cases, 11.2%). Unknown viral disease(20 case, 6.1%), Rota viral infection(19 case, 5.8%), Porcine reproductive & respiratory syndrome(PRRS; 15 case 4.5%), Transmissible gastroenteritis(TGE; 12 case, 3.6%). The gastrointestinal disease, such as Colibacillosis, Salmonellosis, Swine dysentery, Clostridial infection, Rotaviral infection, TGE, Porcine epidemic diarrhea(PED) and Ballantidiosis occured pro- dominently in the period of pre- and post- weaning, which were 178 cases(53.8%) and not related to occurrence according to age and season. The respiratory diseases were Atrophic rhinitis(AR), Swine enzootic pneumonia, Pneumonic pasteurellosis, Pleuropneumonia, Branchopneumonia, PRRS and which were 48 cases(14.5%) and higher prevalent in spring and summer. The viral diseases was 73 cases(22.1%) that occurred in the period of 5 weeks piglet and prevalent mainly in spring. The bacterial diseases were 188 cases(56.8%) that were not related to occurrence according to age and season. Salmonellosis was prevalent in 3 to 5 weeks piglet and mainly occurred in summer. Viral septicemia and rotaviral infection occurred after 5 weeks piglets intensively and 3 to 5 weeks, respectively. And the both occurred without relation with season. PRRS occurred after 4 weeks piglet and prevalent in summer. TGE occurred 1 to 7 days old piglets and prevalent in spring and winter. Hematologic values of anemia was decrease in number of Red Blood Cell, concentration of Hemoglobin and Hematocrit. Amikacin, cephalothin, colistin, norfloxacin were effective to E coli, and amikacin, cephalothin, nortloxacin, neomycin were effective to Salmonellra spp. but clindamycin, erythromycin, penicillin, sulfonamides were resistant to E coli and Salmonella spp.