RESUMO
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.
RESUMO
The Rho GTPases are the sub-group of Ras super family and identified in all eukaryotes. The Rho GTPases effect different cellular signaling pathways involved in a number of diseases such as cancer, neurological and cardiovascular disorders. Members of Rho GTPases including RhoA, RhoC and Rac1 play a major role in regulation of apoptosis in different kind of stress conditions. Here we investigated the Rho GTPase activating protein 15 [ArhGAP15] gene knock-down effect on apoptosis induced by ethanol in bovine fibroblast cells. The bovine Fibroblast cells were treated and transfected with two different concentrations [50 and 100 nM] of ArhGAP15 siRNA for 48 h respectively. Both concentrations of siRNA were effective and the results of RT-PCR revealed an efficient knock-down of ArhGAP15 mRNA in fibroblast cells. Further, the normal cells exposed to a 100 mM ethanol concentration showed a reduction in cell viability and induced the ratio of apoptosis related Bax/Bcl-2 proteins compared with ArhGAP15 siRNA transfected ethanol treated cells. Ethanol also increased caspase-3 expression in normal fibroblast cells compared with transfected cells. The ArhGAP15 knock-down cells treated with ethanol decreased Bax/Bcl-2 ratio and lower caspase-3 protein levels in ArhGAP15 knocked-down cells. Our results suggest that apoptosis induced by ethanol involves the activation of Rho GTPase activating protein 15 and silencing of the said gene protects apoptosis