Antibody response against Escherichia coli heat-stable enterotoxin expressed as fusions to flagellin.
The heat-stable toxin (ST) produced by enterotoxigenic Escherichia coli strains causes diarrhoea by altering the fluid secretion in intestinal epithelial cells. Here, the effectiveness of a flagellin fusion protein of Salmonella containing a 19-amino-acid sequence derived from the ST sequence (FLA--ST) in generating antibodies capable of neutralizing the toxic activity of ST was evaluated. This fusion protein, and an alternative construction where two cysteine residues in the ST sequence were substituted by alanines (ST(mt)), were delivered to the immune system by three distinct strategies: (i) orally, using an attenuated Salmonella strain expressing FLA--ST; (ii) intraperitoneally, by injection of purified FLA--ST; (iii) orally, using attenuated Salmonella carrying a eukaryotic expression plasmid (pCDNA3) with the gene encoding FLA-ST. The results showed that the flagellin system can be used as a carrier to generate ST-neutralizing antibodies. However, it should be mentioned that humoral immune response against ST was only obtained when the mutated ST sequence was employed. FLA-ST was found to be non-immunogenic when delivered via the oral route with attenuated Salmonella strains. However, a flagellin antibody response was obtained by immunizing mice with Salmonella carrying pCDNA3/FLA-ST(mt). Oral immunization with Salmonella carrying the eukaryotic expression plasmid (pCDNA3/FLA--ST(mt)) seems to be a promising method to elicit an appropriate response against fusions to flagellin.
Pereira
Cátia M
CM
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Botucatu, 862, CEP 04023-062, São Paulo, Brazil1.
Cabilio Guth
Beatriz E
BE
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Botucatu, 862, CEP 04023-062, São Paulo, Brazil1.
Sbrogio-Almeida
Maria Elisabete
ME
Divisão de Desenvolvimento Tecnológico e Produção, Instituto Butantan, Avenida Vital Brasil 1500, CEP 05503-900, São Paulo, Brazil2.
Castilho
Beatriz A
BA
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Botucatu, 862, CEP 04023-062, São Paulo, Brazil1.
D000818:Animals; D000833:Animals, Suckling; D000917:Antibody Formation; D001427:Bacterial Toxins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001428:Bacterial Vaccines / Q000276:immunology; D004768:Enterotoxins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005408:Flagellin / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D012486:Salmonella typhimurium / Q000235:genetics* / Q000276:immunology; D014613:Vaccines, Attenuated / Q000276:immunology
D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D014613:Vaccines, Attenuated; C034151:heat stable toxin (E coli); D005408:Flagellin