Construction of a potential live oral bivalent vaccine for typhoid fever and cholera-Escherichia coli-related diarrheas.
We used the Salmonella typhi galactose epimerase (galE) mutant strain Ty21a, shown to be a safe, effective, living, attenuated oral typhoid vaccine, as a recipient for a recombinant plasmid containing the gene for production of the nontoxic B subunit of the heat-labile enterotoxin of Escherichia coli. The S. typhi derivative, strain SE12, produced heat-labile enterotoxin subunit B that was structurally and immunologically indistinguishable from heat-labile enterotoxin subunit B produced by strains of E. coli harboring the same plasmid. Tests in mice and guinea pigs showed that strain SE12 was safe when given orally and was capable of inducing a significant antitoxic antibody response when injected parenterally. Moreover, it retained the galactose sensitivity of the parent strain, preserving its utility as a typhoid vaccine. This strain may prove to be a useful live oral bivalent vaccine strain for typhoid fever and cholera-E. coli-related diarrheas.
D000284:Administration, Oral; D000818:Animals; D001427:Bacterial Toxins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002772:Cholera Toxin / Q000276:immunology*; D003967:Diarrhea / Q000517:prevention & control; D004768:Enterotoxins / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology; D029968:Escherichia coli Proteins; D006168:Guinea Pigs; D051379:Mice; D010957:Plasmids; D012485:Salmonella typhi / Q000276:immunology; D014435:Typhoid Fever / Q000276:immunology / Q000517:prevention & control; D014436:Typhoid-Paratyphoid Vaccines / Q000276:immunology*
D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D014436:Typhoid-Paratyphoid Vaccines; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli