جستجوی مقالات مرتبط با کلیدواژه « pertussis toxin » در نشریات گروه « پزشکی »

Some resources have suggested that genetically inactivated pertussis toxoid (PTs) bear a more protective effect than chemically inactivated products. This study aimed to produce new version of PT, by cloning an inactive pertussis toxin S1 subunit (PTS1) in a fusion form with N-terminal half of the listeriolysin O (LLO) pore-forming toxin.

Deposited pdb structure file of the PT was used to model an extra disulfide bond. Codon-optimized ORF of the PTS1 was used to make recombinant constructs of PTS1 and LLO-PTS1 in the pPSG-IBA35 vector. The recombinant PTS1 and LLO-PTS1 proteins were expressed in BL21 DE3 and SHuffle T7 strains of E. coli and purified by affinity chromatography. Cytotoxic effects of the recombinant proteins were examined in the MCF-7 cell line.

The purity of the products proved to be more than 85%, and the efficiency of the disulfide bond formation in SHuffle T7 strain was higher than BL21 DE3 strain. No cytotoxicity of the recombinant proteins was observed in MCF-7 cells. Soluble recombinant PTS1 and LLO-PTS1 proteins were produced in SHuffle T7 strain of E. coli with high efficiency of disulfide bonds formation.

The LLO-PTS1 with corrected disulfide bonds was successfully expressed in E. coli SHuffle T7 strain. Due to the safety for human cells, this chimeric molecule can be an option to prevent pertussis disease if its immunostimulatory effects would be confirmed in the future.

Lactic acid bacteria such as Lactococcus (L.) lactis are powerful tools that can function as live delivery vectors and heterologous protein expression hosts in development of novel vaccines. Pertussis toxin (PT) and filamentous hemagglutinin (FHA) are important virulence factors of Bordetella (B.) pertussis and constitute the major components of commercially available acellular pertussis (aP) vaccines. The purpose of the present study was to express F1S1 fusion protein, consisted of the N-terminal region of S1 subunit from PT and FHA type 1 immunodominant domain by L. lactis and to evaluate its immunogenicity. The fusion gene composed of sequences encoding the F1S1 and the signal peptide of usp45 fragments (SECF1S1) was codon optimized for protein production in L. lactis and was synthesized and inserted in-frame inside pNZ8149 plasmid. The resulting pNZ8149-SECF1S1 construct was introduced by electroporation into L. lactis cells (LL-F1S1). BALB/c mice were subcutaneously immunized with LL-F1S1 or commercial DTaP vaccine. The immune responses were investigated. The LL-F1S1-immunized mice produced significant levels of specific IFN-g compared to their respective controls and DTaP-immunized mice. The F1S1- specific IgG antibody response was lower in LLF1S1- immunized mice while the IgG2a/IgG1 ratio was higher in this group compared to the DTaP-immunized mice. Moreover, anti-F1S1 IgA antibodies were only detected in the lung homogenates of the LL-F1S1- immunized mice, suggesting the induction of a mucosal immune response. These results indicate the feasibility of expression of F1S1 fusion protein in L. lactis. This recombinant bacterium could induce mucosal and Th1-type systemic immune responses following subcutaneous administration.

  Among hospitalized patients, Staphylococcus aureus (S. aureus) infections pose a serious health threat. The present study investigated the frequency of biofilm forming genes among clinical isolates S. aureus and their susceptibility to antibiotics. The clinical samples were analyzed via standard biochemical assays for identifying different bacterium, which was then confirmed using the multiplex colony PCR method. Those samples identified as S. aureus were examined for the presence of the cna, fnbA, fnbB and pvl genes. The antibiotic susceptibility of the S. aureus isolates was then tested. Using the standard biochemical assay approach, 54 S. aureus strains were identified. However, when using the multiplex PCR method 50 S. aureus strains were identified among the clinical samples. The in vitro biofilm formation assays determined 3 (6%) strains of S. aureus to be strong biofilm forming, 15 (30%) of the isolates were determined to be moderate biofilm forming and, 32 (64%) were determined to be weak biofilm forming. Among the isolated strains, the specific frequencies of the biofilm forming genes were determined to be 31 (62%) for cna, 35 (70%) for fnbA, 13 (26%) for fnbB and 1 (2%) for pvl. In 11 (22%) of the isolated strains fnbA, fnbB and cna genes were all present. All strains were determined to be penicillin, amoxicillin and clavulanic acid resistant. Due to the increase of the antibiotic resistance in biofilm producing S. aureus strains, rapid identification of antibiotic resistance can help to eliminate the infection effectively

After decades of containment, pertussis disease, caused by Bordetella pertussis seems to be re-emerging and still remains a major cause of reported vaccine-preventable deaths worldwide. The current licensed whole-cell vaccines display reactogenicity while acellular vaccines are expensive and do not induce Th1-type immune responses that are required for optimum protection against the disease. Thus, there is an urgent need to develop new vaccines and the recombinant technology seems to be the method of choice for this purpose. The present study was an attempt to develop a new, simplified, cost-effective and well-defined vaccine against Bordetella pertussis, with capacity to induce a Th1 response.
A fusion DNA fragment encoding the N-terminal region of pertussis toxin S1 subunit and filamentous hemagglutinin type 1 immunodominant domain was constructed and the corresponding fusion protein (F1S1) was produced in Escherichia coli. F1S1 in conjunction with imiquimod was administered by subcutaneous (SC) and intranasal (IN) routes to BALB/c mice.
This vaccine formulation could elicit high levels of IFN-γ, serum IgG (with higher IgG2a/IgG1 ratio) and lung IgA after the SC and, to a lesser extent, following the IN administration.
Our results indicate that the above-mentioned important proteins of B. pertussis could be successfully produced in E. coli as a single fusion protein. Furthermore, this protein could induce proper systemic and mucosal immune responses after administration via SC or IN routes.