Abstract: Substantially pure enterotoxins of Shigella flexneri 2a are described, along with a method for obtaining the same, antibodies having binding specificity to the enterotoxins and a method for use of the enterotoxins to develop a non-reactogenic Shigella flexneri 2a vaccine candidate.

Abstract: Substantially pure enterotoxins of Shigella flexneri 2a are described, along with a method for obtaining the same, antibodies having binding specificity to the enterotoxins and a method for use of the enterotoxins to develop a non-reactogenic Shigella flexneri 2a vaccine candidate.

Abstract: Method of isolating deletion mutants of Vibrio cholerae, wherein the deletion is predetermined by digestion with restriction endonucleases of known specificity. The deletions are inserted into the Vibrio cholerae chromosome by in vivo recombination between a plasmid carrying the desired deletion, with adjacent flanking sequences, and the Vibrio cholerae chromosome. The invention includes the isolation and characterization of a new Vibrio cholerae strain, (ATCC No. 55456), having a deletion in the tox gene, as defined by Acc I, Xba I, Cla I and/or restriction endonuclease sites, and carrying a mercury resistance gene. The invention also includes vaccines for protecting against the symptoms of cholera as well as methods for achieving this protection.

Abstract: An oligonucleotide comprises a DNA segment capable of hybridizing to DNA from enteroaggregative E. coli bacteria with high sensitivity and specificity. A recombinant vector comprises a vector carrying the oligonucleotide of the invention, the vector being capable of replication in a host. A host is transformed with the recombinant vector of the invention. A method of detecting the presence of enteroaggregative E. coli DNA in a biological sample with high sensitivity and specificity comprises adding to the sample the labeled oligonucleotide of the invention under conditions effective to promote hybridization thereof to the sample's DNA, and detecting the presence of hybridized labeled DNA. A method of detecting the presence of enteroaggregative E. coli RNA in a sample with high sensitivity and specificity comprises adding to the sample the oligonucleotide of the invention under conditions effective to promote hybridization thereof to the sample's RNA and detecting the presence of hybridized labeled RNA-DNA.

Abstract: This invention relates to a method of isolating deletion mutants of Vibrio cholerae, wherein the deletion is predetermined by digestion with restriction endonucleases of known specificity. The deletions are inserted into the Vibrio cholerae chromosome by in vivo recombination between a plasmid carrying the desired deletion, with adjacent flanking sequences, and the Vibrio cholerae chromosome. The invention includes the isolation and characterization of a new Vibrio cholerae strain having a deletion in the tox gene, as defined by Acc I, Xba I, Cla I and/or Hind III restriction endonuclease sites.

Abstract: This invention relates to a method of isolating deletion mutants of Vibrio cholerae, wherein the deletion is predetermined by digestion with restriction endonucleases of known specificity. The deletions are inserted into the Vibrio cholerae chromosome by in vivo recombination betweem a plasmid carrying the desired deletion, with adjacent flanking sequences, and the Vibrio cholerae chromosome. The invention includes the isolation and characterization of a new Vibrio cholerae strain having a deletion in the tox gene, as defined by Acc I restriction endonuclease sites.