Expression and characterization of cholera toxin B-pneumococcal surface adhesin A fusion protein in Escherichia coli: ability of CTB-PsaA to induce humoral immune response in mice.
ABSTRACT Cholera toxin B subunit (CTB) is responsible for CT holotoxin binding to the cell and has been described as a mucosal adjuvant for vaccines. In this work, the ctxB gene was genetically fused to the psaA gene from Streptococcus pneumoniae, a surface protein involved in its colonization in the host that is also considered a vaccine antigen candidate against this pathogen. The CTB-PsaA fusion protein was expressed in Escherichia coli, and the purified protein was used for intranasal immunization experiments in Balb/C mice. CTB-PsaA was able to induce both systemic and mucosal antibodies evaluated in serum, saliva, and in nasal and bronchial wash samples, showing that CTB-PsaA is a promising molecule to be investigated as S. pneumoniae vaccine antigen candidate.
Article: Cloning and Expression of CtxB-StxB in Esherichia coli: A challenge for Improvement of Immune Response Against StxB[show abstract] [hide abstract]
ABSTRACT: Cholera toxin B subunit (CtxB) is a homopantameric, nontoxic subunit of cholera toxin that is responsible for its binding to the cell and has been known as a mucosal adjuvant for vaccines that could increase homoral and mocusal immunity response. In this work, the CtxB gene was fused to the StxB gene from Shigella dysenteriae type I a vaccine antigen candidate against this pathogen, by a nonfurin linker then ligated with pGEM vector and subcloned in the pET28a(+) as an expression vector . The CtxB-StxB fusion protein was expressed in Escherichia coli, and purified by a Ni-NTA resin column, then detected molecular weight and immunogenicity by SDS-PAGE and Western-blot. StxB has low molecular weight, so immune response against it is low, while CtxB is a potent mucosal adjuvant. In this method, the CtxB-StxB fusion protein was expressed in Escherichia coli in order to use its natural adjuvanticity of the CtxB which will enhance immune response against StxB, as well as, it will produce immune response against both shiga and cholera toxins.Iranian Journal of Pharmaceutical Sciences. 01/2011; 7:185-190.
Article: Intranasal immunization with the cholera toxin B subunit-pneumococcal surface antigen A fusion protein induces protection against colonization with Streptococcus pneumoniae and has negligible impact on the nasopharyngeal and oral microbiota of mice.[show abstract] [hide abstract]
ABSTRACT: One of the candidate proteins for a mucosal vaccine antigen against Streptococcus pneumoniae is PsaA (pneumococcal surface antigen A). Vaccines targeting mucosal immunity may raise concerns as to possible alterations in the normal microbiota, especially in the case of PsaA, which was shown to have homologs with elevated sequence identity in other viridans group streptococci. In this work, we demonstrate that intranasal immunization with a cholera toxin B subunit-PsaA fusion protein is able to protect mice against colonization with S. pneumoniae but does not significantly alter the natural oral or nasopharyngeal microbiota of mice.Infection and Immunity 09/2006; 74(8):4939-44. · 4.16 Impact Factor
Article: Production of human papillomavirus type 16 L1 virus-like particles by recombinant Lactobacillus casei cells.[show abstract] [hide abstract]
ABSTRACT: Infections with human papillomavirus type 16 (HPV-16) are closely associated with the development of human cervical carcinoma, which is one of the most common causes of cancer death in women worldwide. At present, the most promising vaccine against HPV-16 infection is based on the L1 major capsid protein, which self-assembles in virus-like particles (VLPs). In this work, we used a lactose-inducible system based on the Lactobacillus casei lactose operon promoter (plac) for expression of the HPV-16 L1 protein in L. casei. Expression was confirmed by Western blotting, and an electron microscopy analysis of L. casei expressing L1 showed that the protein was able to self-assemble into VLPs intracellularly. The presence of conformational epitopes on the L. casei-produced VLPs was confirmed by immunofluorescence using the anti-HPV-16 VLP conformational antibody H16.V5. Moreover, sera from mice that were subcutaneously immunized with L. casei expressing L1 reacted with Spodoptera frugiperda-produced HPV-16 L1 VLPs, as determined by an enzyme-linked immunosorbent assay. The production of L1 VLPs by Lactobacillus opens the possibility for development of new live mucosal prophylactic vaccines.Applied and Environmental Microbiology 02/2006; 72(1):745-52. · 3.83 Impact Factor