A recombinant Escherichia coli heat-stable enterotoxin b (STb) fusion protein eliciting neutralizing antibodies |
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Authors: | J.Daniel Dubreuil,Ann Letellier,José e Harel |
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Affiliation: | Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Montreal University, PO Box 5000, 3200 Sicotte, St.-Hyacinthe, Que. J2S 7C6, Canada |
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Abstract: | Abstract STb is a heat-stable enterotoxin elaborated by enterotoxigenic Escherichia coli strains associated with weaning piglets and is responsible for diarrhoea in those animals. The maltose binding protein (MBP) of E. coli was used as a carrier for STb, a poorly immunogenic molecule. Constructions were produced where the gene coding for mature STb toxin (MBP-STb) and a fragment of the gene spanning the major epitopic region of STb (AA8–AA30)(MBP-STb2) were fused to malE gene coding for MBP. The fusion proteins accumulated in the periplasm and were detected with a polyclonal antibody raised against the purified toxin. MBP-STb induced secretion in the biological model whereas MBP-STb2 was non-toxic. Immunization of rabbits evoked an antibody response to STb for these two fusion proteins. However, only MBP-STb elicited antibodies that effectively neutralized the toxicity of pure STb toxin as determined in the rat loop assay. |
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Keywords: | Escherichia coli STb enterotoxin Biological activity Fusion protein Neutralizing antibody |
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