Background: TSA (thiol-specific antioxidant antigen) is the immune-dominant antigen of Leishmania major and is considered to be the most promising candidate molecule for a recombinant or DNA vaccine against leishmaniasis. The aim of the present work was to express a plasmid containing the TSA gene in eukaryotic cells. Methods: Genomic DNA was extracted, and the TSA gene was amplified by polymerase chain reaction (PCR). The PCR product was cloned into the pTZ57R/T vector, followed by subcloning into the eukaryotic expression vector pcDNA3 (EcoRI and HindIII sites). The recombinant plasmid was characterised by restriction digest and PCR. Eukaryotic Chinese hamster ovary cells were transfected with the plasmid containing the TSA gene. Expression of the L. major TSA gene was confirmed by sodium dodecyl sulphate–polyacrylamide gel electrophoresis and Western blotting. Results: The plasmid containing the TSA gene was successfully expressed, as demonstrated by a band of 22.1 kDa on Western blots. Conclusion: The plasmid containing the TSA gene can be expressed in a eukaryotic cell line. Thus, the recombinant plasmid may potentially be used as a DNA vaccine in animal models.

PURPOSE: FimH (the adhesion fragment of type 1 fimbriae) is implicated in uropathogenic Escherichia coli (UPEC) attachment to epithelial cells through interaction with mannose. Recently, some studies have found that UPEC can thrive intracellularly causing recurrent urinary tract infection (UTI). Almost all vaccines have been designed to induce antibodies against UPEC. Yet, the humoral immune response is not potent enough to overcome neither the primary UTI nor recurrent infections. However, DNA vaccines offer the possibility of inducing cell mediated immune responses and may be a promising preventive tool. MATERIALS AND METHODS: In this study, we employed two different open reading frames within mammalian (mam) and wild type (wt) codons of fimH gene. Optimized fragments were cloned in pVAX-1. Expression of the protein in COS-7 was confirmed by western blot analysis after assessing pVAX/fimH(mam) and pVAX/fimH(wt). The constructs were injected to BALB/c mice at plantar surface of feet followed by electroporation. RESULTS: The mice immunized with both constructs following booster injection with recombinant FimH showed increased interferon-gamma and interleukin-12 responses significantly higher than non-immunized ones (p<0.05). The immunized mice were challenged with UPEC and then the number of bacteria recovered from the immunized mice was compared with the non-immunized ones. Decreased colony count in immunized mice along with cytokine responses confirmed the promising immune response by the DNA vaccines developed in this study. CONCLUSION: In conclusion, DNA vaccines of UPEC proteins may confer some levels of protection which can be improved by multiple constructs or boosters.
Animals ; Antibodies ; Bacteria ; Blotting, Western ; Clone Cells ; Codon* ; DNA* ; Electroporation ; Epithelial Cells ; Foot ; Immunity, Cellular* ; Immunity, Humoral ; Interferon-gamma ; Interleukin-12 ; Mannose ; Mice ; Open Reading Frames ; Urinary Tract Infections* ; Uropathogenic Escherichia coli ; Vaccines ; Vaccines, DNA

OBJECTIVE: This study aimed to investigate the effects of Montanide ISA-720 and Naloxone (NLX) in Hepatitis B surface antigen (HBsAg) vaccine formulation on cytokine and long-lasting antibody responses. METHODS: First, the HBsAg was formulated in Montanide ISA-720 adjuvant and Naloxone at 5 and 10 mg/kg. The experimental mice were immunized three times at a 2-week interval, and then IL-4, IL-2, TNF-α, and IFN-γ cytokines; long-lasting IgG antibody responses 220 days after the last shot; and IgG1/IgG2a isotypes were assessed by ELISA. RESULTS: The HBsAg-Alum group exhibited the highest IL-4 cytokine response among the experimental groups, whereas NLX in HBsAg-MON720 vaccine formulation did not affect cytokine responses. In addition, NLX in Alum-based vaccine suppressed IL-4 cytokine response and increased the IL-2/IL-4 cytokine ratio. Moreover, HBsAg-MON720 was more potent than HBsAg-Alum in the induction of antibody responses, and NLX in Alum- and MON720-based vaccines induced long-lasting antibody responses. CONCLUSION NLX in Alum-based vaccine decreased IL-4 cytokine response, increased IL-2/IL-4 cytokine ratio, and improved long-lasting humoral immune responses in both vaccine formulations. Therefore, the adjuvant activity of NLX in the vaccine formulation depends on the type of adjuvant and the nature of the antigen in the vaccine formulation.
Adjuvants, Immunologic/pharmacology* ; Alum Compounds ; Animals ; Cytokines ; Hepatitis B Surface Antigens ; Hepatitis B Vaccines ; Immunity, Humoral ; Immunoglobulin G ; Interleukin-2 ; Interleukin-4 ; Mice ; Mice, Inbred BALB C ; Mineral Oil ; Naloxone/pharmacology* ; Tumor Necrosis Factor-alpha