• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.10 no.1
• /
• pp.73-81
• /
• 2024

Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by the SARS-CoV-2 coronavirus, which had been identified in Wuhan, China, in December 2019. COVID-19 is a serious threat to human health and spread worldwide. World Health Organization (WHO) has declared the COVID-19 pandemic. It is important that vaccines and therapeutics are developed to control COVID-19. Among these, vaccines using COVID-19 mRNA platforms have various advantages, including a short development cycle, an easy industrialization, a simple production process, flexibility for new variants, and the capacity to induce better immune responses. This review summarizes the structure and characteristics of coronaviruses and introduces the use of non-clinical pharmacokinetic evaluation with C-14 in mRNA vaccine development. The in vitro stability of C-14 labeled mRNA carrier ([¹⁴C]mRNA carrier) was evaluated and found to be stable for up to 144 hours in rat serum. The [¹⁴C]mRNA carrier was distributed mostly to the administration site in rats, but slowly distributed to other organs after 48 hours. Most of the [¹⁴C]mRNA carrier remained in the administered muscle and was slowly excreted from the body through urine after 72 hours. There was no statistical difference in the distribution and excretion after intramuscular administration of the [¹⁴C]mRNA carrier to male and female rats. Through this paper, it is expected to contribute to the development of drug carriers through various studies using C-14.

• Journal of Veterinary Science
• /
• v.25 no.1
• /
• pp.4.1-4.14
• /
• 2024

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 10^6.9 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.