Salmonella vector induces protective immunity against Lawsonia and Salmonella in murine model using prokaryotic expression system

Background@#Lawsonia intracellularis is the causative agent of proliferative enteropathy and is associated with several outbreaks, causing substantial economic loss to the porcine industry. @*Objectives@#In this study, we focused on demonstrating the protective effect in the mouse model through the immunological bases of two vaccine strains against porcine proliferative enteritis. @*Methods@#We used live-attenuated Salmonella Typhimurium (ST) secreting two selected immunogenic LI antigens (Lawsonia autotransporter A epitopes and flagellin [FliC]-peptidoglycan-associated lipoprotein-FliC) as the vaccine carrier. The constructs were cloned into a Salmonella expression vector (pJHL65) and transformed into the ST strain (JOL912). The expression of immunogenic proteins within Salmonella was evaluated via immunoblotting. @*Results@#Immunizing BALB/c mice orally and subcutaneously induced high levels of LI-specific systemic immunoglobulin G and mucosal secretory immunoglobulin A. In immunized mice, there was significant upregulation of interferon-γ and interleukin-4 cytokine mRNA and an increase in the subpopulations of cluster of differentiation (CD) 4+ and CD 8+ T lymphocytes upon splenocytes re-stimulation with LI antigens. We observed significant protection in C57BL/6 mice against challenge with 106.9 times the median tissue culture infectious dose of LI or 2 × 109 colony-forming units of the virulent ST strain. Immunizing mice with either individual vaccine strains or co-mixture inhibited bacterial proliferation, with a marked reduction in the percentage of mice shedding Lawsonia in their feces. @*Conclusions@#Salmonella-mediated LI gene delivery induces robust humoral and cellular immune reactions, leading to significant protection against LI and salmonellosis.

Recharacterization of the Canine Adenovirus Type 1 Vaccine Strain based on the Biological and Molecular Properties

Canine adenovirus type 1 (CAV-1) infection results in hepatitis in dogs. In this study, we investigated the biologic and genetic characteristics of the CAV-1 vaccine strain (CAV1V) to improve quality control about CAV vaccine. The identity of CAV1V as CAV-1 was confirmed based on its cytopathic effects and the results of hemagglutination (HA) and immunofluorescence assays, and electron microscopy. The CAV1V strain reached 10(7.5) TCID(50)/mL in MDCK cells at 4 days post-inoculation and exhibited hemmagglutination activity of 256 U using guinea pig erythrocytes. Intranuclear fluorescence in the infected cells was observed and typical adenoviruses were observed in electon microscope. CAV1V strain was identified as a CAV-1 strain by nucleotide sequence analysis. In a comparison of the nucleotide sequences of the fiber genes of several CAV strains, CAV1V showed the highest similarity (99.8%) with the GLAXO strain, which was isolated in Canada. Our biological characterization of CAV1V will facilitate quality control of the canine hepatitis vaccine.

Ameliorative Effect of Palmiwon on Polychlorinated Biphenyl (PCB, Aroclor 1254)-Induced Spermiotoxicity in the Rat / 대한남성과학회지

PURPOSE: Polychlorinated biphenyls (PCBs, Aroclor 1254), synthetic chlorinated organic compounds, are known to decrease thyroid function, sperm count, and fertility, and increase the risk of testicular cancer; they may have serious effects on male reproduction. The aim of this study was to investigate the possible protective role of palmiwon on PCB-induced spermiotoxicity in rats. MATERIALS AND METHODS: 90-day-old male Sprague Dawley rats were randomly divided into three groups, each consisting of ten animals. The control group (Group I) received corn oil, the second group of rats (Group II) was administered 2 mg/kg body weight/day of Aroclor 1254+corn oil intraperitoneally for 30 days. The third group of rats (Group III) was treated with 2 mg/kg body weight/day of Aroclor 1254+corn oil intraperitoneally plus palmiwon (300 mg/day) orally for 30 days. Twenty-four hours after the last treatment, the animals were killed by decapitation. Their serum testosterone levels was measured before and after the experimental medication was taken, and the number and motility of sperm, which had been collected from the cauda epididymal region, were evaluated. RESULTS: The results of this experiment show that treatment with palmiwon significantly improved sperm motility and number in rats that had been exposed to PCBs. There was no marked difference in body weight, testis weight, or epididymis weight among the groups. Nor were there any significant pathological differences in the testes among the groups. CONCLUSIONS: Palmiwon has the potential for treating PCB-induced spermiotoxicity. More experiments with larger samples and a longer period of treatment are needed.