Salmonella-based vaccines fight against fatal diseases

Existing vaccines are inadequate for protecting vulnerable populations against fatal diseases including hepatitis B, tuberculosis, cholera, typhoid fever, AIDS and pneumonia.

Now, Qingke Kong and his colleagues at the Biodesign Institute at Arizona State University have shown how a powerful new class of therapeutics, known as recombinant attenuated Salmonella vaccines (RASV), can make vaccines safer and more effective.

The group, under the direction of Dr Roy Curtiss, chief scientist at Biodesign's Center for Infectious Diseases and Vaccinology, demonstrated that a modified strain of Salmonella showed a five-fold reduction in virulence in mice, while preserving strong immunogenic properties.   

One of the most promising strategies for new vaccine development is to use a given pathogen as a cargo ship to deliver key antigens from the pathogen that researchers wish to vaccinate against.

Salmonella, the bacterium responsible for food poisoning, has proven particularly attractive for this purpose, as Curtiss explains: "Orally-administered RASVs stimulate all three branches of the immune system stimulating mucosal, humoral and cellular immunity that will be protective, in this case, against a majority of pneumococcal strains causing disease."

Recombinant Salmonella is a highly versatile vector—capable of delivering disease-causing antigens originating from viruses, bacteria and parasites.

An attenuated Salmonella vaccine against pneumonia, developed in the Curtiss lab, is currently in FDA phase 1 clinical trials.

The study has been published in the Journal of Immunology.