ABSTRACT
Background: Cholera is an acute intestinal infection caused by Vibrio cholera (V. cholera). The development of antibodies against specific V. cholerae may have a therapeutic effect. In the present research, we investigated the protective effect of egg yolk Immunoglobulin (IgY), which was produced by immunizing hens with formaldehyde-killed V. cholerae O1 and subsequently the isolated IgY was orally administrated to the V. cholerae O1 infected mice for evaluation of its immunizing capability. Methods: In the current study, hens were immunized three times with formaldehyde-killed V. cholerae O1 (1.5×107 CFU/ml) and an equal volume of adjuvant. The IgY was isolated from egg yolk by polyethylene glycol method. The validity and activity of isolated IgY were confirmed with SDS-PAGE and ELISA methods, respectively. Subsequently IgY was orally administered to suckling mice following challenge with V. cholerae O1. ELISA results showed high antibody titer in the serum and egg yolk. Also, SDS-PAGE analysis showed successful purification of IgY and anti-V. cholerae IgY prevented the death of mice infected with V. cholerae O1. The anti-V. cholera IgY was administered at 2, 4, 6 hr intervals after 3 hr of inoculation of mice with V. cholerae O1. Results: Results showed that the rate of surviving mice (2 mg/ml of IgY) were 60% after 4 hr and 40% after 6 hr and the rate of surviving mice (5 mg/ml of IgY) was 70% after 4 hr and 60% after 6 hr. Conclusion: The findings suggested the egg yolk-driven IgY as a natural antibacterial protein, could be effective in the prevention and treatment of cholera disease.
ABSTRACT
The recent viral infection disease pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global public health crisis. Iran, as one of the countries that reported over five million infected cases by September 2021, has been concerned with the urgent development of effective vaccines against SARS-CoV-2. In this paper, we report the results of a study on potency and safety of an inactivated SARS-CoV-2 vaccine candidate (FAKHRAVAC) in a preclinical study so as to confirm its potential for further clinical evaluation. Here, we developed a pilot-scale production of FAKHRAVAC, a purified inactivated SARS-CoV-2 virus vaccine candidate that induces neutralizing antibodies in Balb/c mice, guinea pigs, rabbits, and non-human primates (Rhesus macaques-RM). After obtaining ethical code of IR.IUMS.REC.1399.566, immunizations of animals were conducted by using either of three different vaccine dilutions; High (H): 10 µg/dose, Medium (M): 5 µg/dose, and Low (L): 1 µg/dose, respectively. In the process of screening for viral seeds, viral strains that resulted in the most severe clinical manifestation in patients have been isolated for vaccine development. The viral seed produced the optimal immunity against SARS-CoV-2 virus, which suggests a possible broader neutralizing ability against SARS-CoV-2 strains. The seroconversion rate at the H-, M-, and L-dose groups of all tested animals reached 100% by 28 days after immunization. These data support the eligibility of FAKHRAVAC vaccine candidate for further evaluation in a clinical trial.
ABSTRACT
Background: Anthrax is a zoonotic disease caused by Bacillus anthracis and it can be deadly in 6 days. Considerable efforts have been conducted toward developing more effective veterinary and human anthrax vaccines because these common vaccines have several limitations. B. anthracis secretes a tripartite toxin, comprising protective antigen (PA), edema factor (EF), and lethal factor (LF). Several studies have shown important role of PA in protection of anthrax. LF and EF induce production of toxin neutralizing antibodies too. PA in fusion form with LF/EF has synergistic effects as a potential subunit vaccine. Methods: In this study, for the first time, a triple chimeric protein called ELP was modeled by fusing three different domains of anthrax toxic antigens, the N-terminal domains of EF and LF, and the C-terminal domain of PA as a high immunogenic antigen using Modeller 9.19 software. Immunogenicity of the ELP was assessed in guinea pigs using enzyme-linked immunosorbent assay (ELISA) test and MTT assay. Results: Theoretical studies and molecular dynamics (MD) simulation results suggest that the ELP model had acceptable quality and stability. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified ELP, its domains, and PA were matched with their molecular size and confirmed by western blotting analysis. In the immune guinea pigs, antibody was produced against all of the ELP domains. It was observed that ELP induced strong humoral response and could protect murine macrophage cell line (RAW 264.7 cells) against anthrax lethal toxin (LeTx). Conclusions: ELP chimeric antigen could be considered as a high immunogenic antigen.
