Dataset Information

Evaluation of the Effect of Promoter Type on the Immunogenicity of the Live Recombinant Salmonella Vaccines Expressing Escherichia Coli Heat-labile Enterotoxins (LTB).

ABSTRACT: Enterotoxigenic Escherichia coli (ETEC)-induced diarrhoea is the second most common cause of death in children in the developing countries. Heat labile toxin (LT) is responsible for ETEC-induced diarrhoea. In the present study, a novel live ETEC vaccine based on subunit B of LT (LTB) expression in attenuated PhoPc Salmonella strain was developed. Herein, we aimed to compare the in-vitro activity of promoters including constitutive tac, IPTG inducible trc, and in-vivo-inducible (nirB and nirB78-23) in PhoPc. Additionally, the ability of these recombinant PhoPc/pLTBs to induce LTB-specific antibody responses in BALB/c mice after nasal immunization was evaluated. In-vitro studies demonstrated that PhoPc has the ability to produce rLTB. Furthermore, nirB promoter directed significantly more LTB expression in PhoPc/pnirBLTB under anaerobic condition without induction compared to the amount of rLTB secreted by PhoPc/ptrcLTB in bacterial soup under uninduced condition (6.06 ± 0.05 vs. 1.4 ± 0.46 ?g/109 cfu, p < 0.01). In addition, the constitutive rLTB expression from tac promoter was more than its expression from uninduced trc promoter in bacterial soup (4.2 ± 0.92 vs. 1.4 ± 0.46 (?g/109 cfu)) and pellet (27.4 ± 0.89 vs. 13.4 ± 1.42 (?g/109 cfu), p < 0.0001). However, the mice immunized with PhoPc/ptrcLTB elicited the superior anti-LTB responses among the PhoPc containing the examined prompters, which were significantly higher than those induced by PhoPc/pnirB78-23LTB and PhoPc/pnirB, 6 weeks after the first immunization. Totally, it could be concluded that in-vitro analysis of promoters for LTB expression in PhoPc may not necessarily predict the recombinant PhoPc immunogenicity.

SUBMITTER: Mohit E

PROVIDER: S-EPMC6447867 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evaluation of the Effect of Promoter Type on the Immunogenicity of the Live Recombinant Salmonella Vaccines Expressing Escherichia Coli Heat-labile Enterotoxins (LTB).

Mohit Elham E Nasr Reza R Ghazvini Kiarash K Bandegi Ahmad Reza AR Akbari Eidgahi Mohammad Reza MR

Iranian journal of pharmaceutical research : IJPR 20180101 Suppl2

Enterotoxigenic Escherichia coli (ETEC)-induced diarrhoea is the second most common cause of death in children in the developing countries. Heat labile toxin (LT) is responsible for ETEC-induced diarrhoea. In the present study, a novel live ETEC vaccine based on subunit B of LT (LTB) expression in attenuated PhoPc Salmonella strain was developed. Herein, we aimed to compare the in-vitro activity of promoters including constitutive tac, IPTG inducible trc ...[more]

PMID: 31086557

Similar Datasets

Project description:There are conflicting reports concerning the impact of prior vector priming on the immunogenicity of recombinant-Salmonella-based vaccines. A comparison of experimental protocols identified two variables which might account for this inconsistency: the potential of the vector strain to colonize the murine gut-associated lymphoid tissue (GALT) and the nature of the foreign antigen subsequently delivered by the recombinant Salmonella construct. The former was investigated by constructing an aroA mutant of the Salmonella enterica serovar Stanley vector previously used in our laboratory. Although the introduction of an aroA mutation had surprisingly little effect on GALT colonization, it did reduce the strength of antilipopolysaccharide (anti-LPS) antibody responses and the impact of vector priming. Studies were also performed to ascertain the extent to which any observed hyporesponsiveness consequent upon vector priming might be determined by the characteristics of the foreign antigen. S. enterica serovar Stanley was used to deliver either of two Escherichia coli antigens, K88 pilus protein or the LT-B toxin subunit, to vector-primed mice. Both serum immunoglobulin G (IgG) and intestinal IgA responses to K88 were completely abolished, and those to LT-B were significantly reduced, as a consequence of vector priming. When similar experiments were performed with an aroA S. enterica serovar Dublin vector, responses to K88 were significantly reduced but those to LT-B were unaffected by vector priming. Paradoxically, a priming infection with this vector induced stronger anti-LPS antibody responses but was less likely to elicit a state of hyporesponsiveness to subsequently presented foreign antigen. The impact of vector priming thus depends on both the Salmonella strain used and the nature of the foreign antigen, but our present data strengthen concerns that preexisting antivector immunity represents a serious threat to the Salmonella-based vaccine strategy.

Dataset Information

Evaluation of the Effect of Promoter Type on the Immunogenicity of the Live Recombinant Salmonella Vaccines Expressing Escherichia Coli Heat-labile Enterotoxins (LTB).

Publications

Evaluation of the Effect of Promoter Type on the Immunogenicity of the Live Recombinant <i>Salmonella</i> Vaccines Expressing <i>Escherichia Coli</i> Heat-labile Enterotoxins (LTB).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets