Eat the Raw Cookie Dough: Salmonella Vaccine Development by Exploring Salmonella Toxins
Abstract
Salmonella is a highly antibiotic-resistant Gram-negative bacteria that is the most reported bacterial food-borne disease. Despite increases in awareness and sanitation, the incidence of Salmonella has continued to increase. A vaccine to combat this important pathogen in agriculturally important animals would help to protect humans. AB5 toxins are key bacterial virulence factors and have been used as vaccine antigens. We have previously characterized an AB5 toxin of S. typhimurium, called ArtAB, to better understand its role in pathogenesis. We hypothesized that other AB5 toxins can be found using Salmonella whole genome sequence searches. We identified a homologous toxin with 31% identity to ArtAB in S. Montevideo (sub-cyto like, SCL). Using PCR, we have also identified SCL in isolates of S. typhimurium and cloned it into a plasmid for expression in E.coli. Protein purification using D-galactose affinity was not successful to purify the Scl A and B subunits, and other methods are currently being explored including cloning the B subunit alone. In addition, we have tested the DNA from bovine fecal samples to determine if the artAB gene is present and will test these samples for SCL in the future. This work will support future studies involving antigen and antibody testing with the goal of animal studies and clinical trials to develop a novel bovine Salmonella vaccine.
Eat the Raw Cookie Dough: Salmonella Vaccine Development by Exploring Salmonella Toxins
Salmonella is a highly antibiotic-resistant Gram-negative bacteria that is the most reported bacterial food-borne disease. Despite increases in awareness and sanitation, the incidence of Salmonella has continued to increase. A vaccine to combat this important pathogen in agriculturally important animals would help to protect humans. AB5 toxins are key bacterial virulence factors and have been used as vaccine antigens. We have previously characterized an AB5 toxin of S. typhimurium, called ArtAB, to better understand its role in pathogenesis. We hypothesized that other AB5 toxins can be found using Salmonella whole genome sequence searches. We identified a homologous toxin with 31% identity to ArtAB in S. Montevideo (sub-cyto like, SCL). Using PCR, we have also identified SCL in isolates of S. typhimurium and cloned it into a plasmid for expression in E.coli. Protein purification using D-galactose affinity was not successful to purify the Scl A and B subunits, and other methods are currently being explored including cloning the B subunit alone. In addition, we have tested the DNA from bovine fecal samples to determine if the artAB gene is present and will test these samples for SCL in the future. This work will support future studies involving antigen and antibody testing with the goal of animal studies and clinical trials to develop a novel bovine Salmonella vaccine.