1. Expression of Streptococcus pneumoniae antigens, PsaA (pneumococcal surface antigen A) and PspA (pneumococcal surface protein A) by Lactobacillus casei.
- Author
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Oliveira ML, Monedero V, Miyaji EN, Leite LC, Lee Ho P, and Pérez-Martínez G
- Subjects
- Adhesins, Bacterial, Bacterial Proteins genetics, Carrier Proteins genetics, Gene Expression, Lacticaseibacillus casei genetics, Lipoproteins genetics, Lipoproteins immunology, Pneumococcal Vaccines genetics, Pneumococcal Vaccines immunology, Pneumococcal Vaccines pharmacology, Recombinant Proteins metabolism, Streptococcus pneumoniae genetics, Bacterial Proteins metabolism, Carrier Proteins metabolism, Lacticaseibacillus casei metabolism, Lipoproteins metabolism, Membrane Transport Proteins
- Abstract
A number of recent research works in lactic acid bacteria aim towards the design of new strains that could be used as live vectors for the delivery of antigens for oral vaccination, or other therapeutic molecules. In this work, an inducible expression system based on the Lactobacillus casei lactose operon promoter was used to express three important surface antigens of Streptococcus pneumoniae in this lactic acid bacterium: a virulence-related pneumococcal surface antigen (PsaA) and two variants of the virulence factor PspA (pneumococcal surface protein A). Expression of the three proteins was induced upon growth on lactose and strongly repressed by glucose. These proteins were produced intracellularly. Also, secretion to the growth medium was achieved by means of a fusion to the secreting and processing signals from the L. casei surface proteinase. Interestingly, while secreted PspA proteins were found in the culture supernatants, PsaA remained trapped in the cell wall. Expression of pneumococcal antigens in a food-grade organism opens an alternative for mucosal vaccination against this important pathogen.
- Published
- 2003
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