Induction of immunocastration in pre-pubertal boars immunized with recombinant gonadotropin-releasing hormone conjugated with Salmonella Typhimurium flagellin fljB.

Immunocastration is an alternative method used to replace surgical castration commonly performed in swine farms. In boars, the main effects of immunocastration are reduction of gonadotropin-releasing hormone (GnRH) and the resulting inhibition of testicular function. The aim of this study was to evaluate immunocastration efficacy in pre-pubertal boars vaccinated with a recombinant GnRH protein conjugated with Salmonella Typhimurium flagellin fljB (STF2). A total of 35 boars were assigned to three groups: the untreated group (n = 5), the surgically castrated group (n = 5), and the immunocastrated group (n = 25). Pigs in the immunocastration group were immunized with the GnRH-STF2 vaccine at pre-pubertal ages 4 and 8 weeks. All experimental pigs were kept for 26 weeks before slaughter. Anti-GnRH antibody levels of immunocastrated pigs were significantly higher than those of untreated pigs (P < 0.001). In contrast, testosterone levels of immunocastrated pigs were significantly lower than those of untreated pigs (P < 0.001). Statistical significances were not found in the body weights and backfat thicknesses of untreated vs. immunocastrated pigs. Weights of the testes and epididymides of immunocastrated pigs were significantly lower than those of untreated pigs (P < 0.001). Testicular tissues of immunocastrated pigs were severely suppressed compared with those of untreated pigs. In conclusion, immunization with the STF2-GnRH vaccine effectively induced immunocastration in pre-pubertal boars.

An immunoproteomic approach for characterization of the outer membrane proteins of Salmonella Gallinarum.

Salmonella enterica serovar Gallinarum (SG) is an important pathogen that causes fowl typhoid in chickens. In order to investigate SG outer membrane proteins (OMPs) as potential vaccine candidate proteins, we established a proteomic map and database of antigenic SG-OMPs. A total of 174 spots were detected by 2DE. Twenty-two antigen-reactive spots were identified as nine specific proteins using PMF. OmpA was the most abundant protein among all of the identified OMPs, and it exhibited seven protein species. We conducted Western blot analysis for the SG-OMPs in order to determine which proteins were cross-reactive to the serovars Salmonella Enteritidis, Salmonella Typhimurium, and SG. Our results indicated that OmpA was considered to be an antigenic cross-reactive protein among the three serovars. This study sheds new light on our understanding of cross-protection among Salmonella serovars.

Reduction of mycoplasmal lesions and clinical signs by vaccination against Mycoplasma hyorhinis.

Porcine mycoplasmal pneumonia is a significant disease problem in the swine industry. The causative agents include Mycoplasma hyopneumoniae and Mycoplasma hyorhinis. M. hyopneumoniae is the major pathogen contributing to the porcine respiratory disease complex, but is difficult to isolate from the respiratory tract and tonsils, whereas M. hyorhinis is not. Although M. hyorhinis is commonly detected in the lungs, the role of M. hyorhinis as a cause of pneumonia remains unclear. Current vaccines for porcine mycoplasmal pneumonia only include M. hyopneumoniae, not M. hyorhinis. M. hyopneumoniae vaccines are widely used, but disease still occurs because of poor vaccine efficacy and possibly the presence of M. hyorhinis. In this study, an inactivated vaccine containing a mixture of M. hyorhinis and M. hyopneumoniae was generated and evaluated for safety, immunogenicity, and protective efficacy against challenge with M. hyorhinis in pigs. The inactivated vaccine induced an antibody response and reduced pneumonic lesions in the lungs and tracheas compared with the non-vaccinated group.

In vitro and in vivo studies of deglycosylated chimeric porcine reproductive and respiratory syndrome virus as a vaccine candidate and its realistic revenue impact at commercial pig production level.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes major economic losses in the swine industry worldwide. Vaccination is the most effective method to control the disease. In a previous study, a chimeric PRRSV named as K418 which had a genome composed of ORF 1 from the FL12 strain and ORF 2-7 from the Korean representative LMY strain was created. We constructed K418DM, K418 with deglycosylated glycoprotein 5 (GP5), to improve its humoral immunity. In the follow-up on in vivo and in vitro virological and serological tests, no back mutation in amino acids of GP5 associated with deglycosylation was shown after 9 passages on MARC-145 cells, whereas only one case of back mutation was detected after single passage in pig. In serological study, K418DM induced higher serum neutralization (SN) antibody and more limited viremia compared with those of K418 virus. In clinical trial and economic analysis, the K418DM elicited SN antibody titers and PRRSV-specific IgG over protection limit. From the economic viewpoint, there was statistically significant reduction in percentage of weak pigs. These results indicated that vaccination with the K418DM may provide enhanced protection for pigs in PRRS endemic situation and increase growth performance in commercial pig farms.

Proteomic analysis of outer membrane proteins in Salmonella enterica Enteritidis.

Salmonella enterica serovar Enteritidis is the predominant agent causing salmonellosis in chickens and other domestic animals. In an attempt to identify antigenic S. Enteritidis outer membrane proteins (OMPs) that may be useful for subunit vaccine development, we established a proteomic map and database of antigenic S. Enteritidis OMPs. In total, 351 and 301 spots respectively from S. Enteritidis strain 270 and strain 350 were detected by twodimensional gel electrophoresis. Fifty-one antigen-reactive spots were detected by antisera on two-dimensional immunoblots and identified as 12 specific proteins by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. OmpA and DNA starvation/ stationary phase protection protein (Dps) were the most abundant proteins among the identified OMPs, comprising 22 and 12 protein species, respectively. Interestingly, we found that the Dps of S. Enteritidis is also antigenic. OmpW was also verified to have high antigenicity. These results show that OmpA, Dps, and possibly OmpW are antigenic proteins. This study provides new insights into our understanding of the immunogenic characteristics of S. Enteritidis OMPs.

An inactivated oil-emulsion fowl Adenovirus serotype 4 vaccine provides broad cross-protection against various serotypes of fowl Adenovirus.

The number of clinical cases of inclusion body hepatitis (IBH) and hydropericardium-hepatitis syndrome (HHS) has been increasing, resulting in considerable economic losses in many countries. Currently, only fowl Adenovirus (FAdV) serotype 4 (FAdV-4) has been reported as the causative agent of HHS, whereas IBH can be caused by all 12 serotypes of FAdV. For protection against HHS, various live and killed FAdV serotype 4 vaccines have been developed. However, there is a concern whether these vaccines composed of FAdV-4 alone could provide protection against IBH, which is caused by other serotypes of virulent FAdVs. To date, there have been no reports evaluating the protective efficacy of the FAdV-4 vaccine against other serotypes of FAdV. Thus, we investigated the cross-protection efficacy of an inactivated oil-emulsion FAdV-4 vaccine against various serotypes of FAdV field isolates. Our study demonstrated that the inactivated oil-emulsion FAdV-4 vaccine could provide broad cross-protection against various serotypes of FAdV in not only vaccinated birds, but also the progenies of vaccinated breeder. Therefore, we conclude that the inactivated oil-emulsion FAdV-4 vaccine could be effective in preventing the spread of various other serotypes of FAdV as well as FAdV-4 infection in the poultry industry.