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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Characterisation of alternative expression vectors for recombinant Bacillus Calmette-Guérin as live bacterial delivery systems

Full text
Author(s):
Larissa V Nascimento ; Carina C Santos [2] ; Luciana CC Leite [3] ; Ivan P Nascimento [4]
Total Authors: 4
Document type: Journal article
Source: Memórias do Instituto Oswaldo Cruz; v. 115, 2020-05-15.
Abstract

BACKGROUND Bacillus Calmette-Guérin (BCG) is considered a promising live bacterial delivery system. However, several proposals for rBCG vaccines have not progressed, mainly due to the limitations of the available expression systems. OBJECTIVES To obtain a set of mycobacterial vectors using a range of promoters with different strengths based on a standard backbone, previously shown to be stable. METHODS Mycobacterial expression vectors based on the pLA71 vector as backbone, were obtained inserting different promoters (PAN, PαAg, PHsp60, PBlaF* and PL5) and the green fluorescence protein (GFP) as reporter gene, to evaluate features such as their relative strengths, and the in vitro (inside macrophages) and in vivo stability. FINDINGS The relative fluorescence observed with the different vectors showed increasing strength of the promoters: PAN was the weakest in both Mycobacterium smegmatis and BCG and PBlaF* was higher than PHsp60 in BCG. The relative fluorescence observed in a macrophage cell line showed that PBlaF* and PHsp60 were comparable. It was not possible to obtain strains transformed with the extrachromosomal expression vector containing the PL5 in either species. MAIN CONCLUSION We have obtained a set of potentially stable mycobacterial vectors with a arrange of expression levels, to be used in the development of rBCG vaccines. (AU)

FAPESP's process: 17/24832-6 - Development of vaccines based on recombinant BCG: Tuberculosis, Pertussis, Pneumococcus and Schistosoma
Grantee:Luciana Cezar de Cerqueira Leite
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 14/01271-0 - Identification of biomarkers of protection and immunological characterization of a novel vaccine candidate against tuberculosis based on Recombinant BCG
Grantee:Carina Carvalho dos Santos
Support Opportunities: Scholarships in Brazil - Doctorate (Direct)