Biomaterial Database

Stabilization of recombinant avirulent vaccine strains in vivo. 1990

R Curtiss, and J E Galan, and K Nakayama, and S M Kelly

Department of Biology, Washington University, St. Louis, MO 63130.

Salmonella strains attenuated by various mutational alterations and expressing heterologous colonization and virulence antigens specified by cloned genes have begun to be widely used as vaccines for oral immunization to induce protective immunity against the pathogens supplying the genes for the colonization or virulence antigens. Problems associated with plasmid instability and/or poor expression of cloned gene products have frequently been encountered and regulatory agencies are now banning use of antibiotic resistance markers in live attenuated vaccine strains. We have therefore developed a balanced lethal host-vector system in which the chromosome of the attenuated vaccine strain contains a deletion mutation that impose a requirement for diaminopimelic acid (DAP), an essential constituent of the rigid layer of the cell wall of all Gram-negative and some Gram-positive microbes. The plasmid cloning vector contains the wild-type allele for this gene allowing the recombinant avirulent Salmonella to be independent of DAP. Since DAP is not prevalent in nature, especially in the animal host, essentially 100% of the surviving avirulent Salmonella recovered from an immunized animal host still contain the recombinant plasmid and express the foreign colonization or virulence antigen. Occasional loss of the plasmid renders the avirulent Salmonella DAP-requiring, which quickly results in DAPless death with lysis of the bacterium to release its antigenic contents, an occurrence which might further enhance the immune response to the foreign colonization or virulence antigen. We describe below strains of bacteria, recombinant vectors and the methods to make use of this system in a diversity of situations for development of live recombinant avirulent vaccines as well as for other potential applications.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003960	Diaminopimelic Acid	A diamino derivative of heptanedioic acid with amino groups at C-2 and C-6 and the general formula (COOH)CH(NH2)CH2CH2CH2CH(NH2)(COOH).	2,6-Diaminopimelic Acid,2,6 Diaminopimelic Acid,Acid, 2,6-Diaminopimelic,Acid, Diaminopimelic
D004251	DNA Transposable Elements	Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.	DNA Insertion Elements,DNA Transposons,IS Elements,Insertion Sequence Elements,Tn Elements,Transposable Elements,Elements, Insertion Sequence,Sequence Elements, Insertion,DNA Insertion Element,DNA Transposable Element,DNA Transposon,Element, DNA Insertion,Element, DNA Transposable,Element, IS,Element, Insertion Sequence,Element, Tn,Element, Transposable,Elements, DNA Insertion,Elements, DNA Transposable,Elements, IS,Elements, Tn,Elements, Transposable,IS Element,Insertion Element, DNA,Insertion Elements, DNA,Insertion Sequence Element,Sequence Element, Insertion,Tn Element,Transposable Element,Transposable Element, DNA,Transposable Elements, DNA,Transposon, DNA,Transposons, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial
D005804	Genes, Lethal	Genes whose loss of function or gain of function MUTATION leads to the death of the carrier prior to maturity. They may be essential genes (GENES, ESSENTIAL) required for viability, or genes which cause a block of function of an essential gene at a time when the essential gene function is required for viability.	Alleles, Lethal,Allele, Lethal,Gene, Lethal,Lethal Allele,Lethal Alleles,Lethal Gene,Lethal Genes
D005822	Genetic Vectors	DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.	Cloning Vectors,Shuttle Vectors,Vectors, Genetic,Cloning Vector,Genetic Vector,Shuttle Vector,Vector, Cloning,Vector, Genetic,Vector, Shuttle,Vectors, Cloning,Vectors, Shuttle