An Attenuated aroA Salmonella typhimurium Vaccine Elicits Humoral and Cellular Immunity to Cloned  -Galactosidase in Mice

Abstract

beta-Galactosidase (GZ) is an intracellular protein that is frequently used to express cloned antigens as fusion proteins in Escherichia coli. Salmonella typhimurium strain SL3261, an attenuated aroA vaccine strain, was used as a carrier for the plasmid pXY411, which directs the expression of GZ in salmonellae (which do not normally produce this protein). The resulting strain--SL3261(pXY411)--expressed GZ as an intracellular antigen. The plasmid was stable in vitro and in vivo and did not significantly alter the behavior of strain SL3261 in mice. Animals intravenously vaccinated with this construct developed circulating antibodies to GZ, as measured by ELISA, and delayed hypersensitivity to the antigen injected in the footpad. These results indicate that attenuated salmonellae may be expected to elicit both humoral and cellular responses to intracellular cloned antigens.

Expression of disulphide-bridge-dependent conformational epitopes and immunogenicity of the carboxy-terminal 19 kDa domain of Plasmodium yoelii merozoite surface protein-1 in live attenuated Salmonella vaccine strains

“…Oligonucleotide primers containing sites for BamHI and SpeI cohesive ends (forward primer, 5' TAGG 3' ; reverse primer, 5' CACACTAGTCTCGAGGCT-GGAAGAACTACAGAATAC 3') were used to amplify the DNA, allowing directional cloning of the MSPl,, EGF-like modules into pTECH2 that had been previously digested with BamHI and SpeI. The bacterial strains used were E. coli Topp 10 (Stratagene), E. coli TG2 (recA) (Sambrook et al, 1989), Salmonella typhimurium SL5338 (galE r-m+) (Brown et al, 1987) and the S. typhimurium vaccine strains : SL3261(aroA) (Hoiseth & Stocker, 1981), BRD726 (AhtrA) (Chatfield et al, 1992), CSaroD (Miller et al, 1989) and C.5046 (htrA::TnphoA) (Johnson et al, 1991) (referred to in this study as C5htrA). Bacteria were grown aerobically in Luria-Bertani (LB) broth supplemented with 50 pg ampicillin ml-l as required.…”

Virulence Attenuation and Live Vaccine Potential of aroA , crp cdt cya , and Plasmid-Cured Mutants of Salmonella enterica Serovar Abortusovis in Mice and Sheep

“…In particular, genetically defined Salmonella vaccines that have been shown to induce protective immunity in various animal models include aroA or aroCD, crp cya, phoPQ, ompR, and htrA mutants (4,9,11,13,14,16,32). Infection with such Salmonella vaccine strains effectively induced cell-mediated and humoral immunity to homologous (8,21,24) or heterologous (11,33,43) antigens.…”

Phase 2 Clinical Trial of AttenuatedSalmonella entericaSerovar Typhi Oral Live Vector Vaccine CVD 908-htrAin U.S. Volunteers

“…These are substrates that the organism cannot scavenge in sufficient quantities in mammalian tissues to sustain growth. Such aro deletion mutants of S. enterica serovar Typhimurium are safe and immunogenic as live oral vaccines in mice and cattle (4,10,12,19). Analogous auxotrophic mutants of serovar Typhi have been prepared as typhoid vaccines and vaccine vectors for humans.…”