A new concept to stimulate mucosal as well as systemic immunity by parenteral vaccination as applied to the development of a live attenuated Salmonella enterica serovar Dublin vaccine.

Abstract

A new concept of slow "drip feeding" that enables activation of mucosal as well as systemic immunity following parenteral vaccination was demonstrated using Salmonella Dublin in a mouse model. The live vaccine candidate, N-RM25, generated from a wild S. Dublin strain utilising metabolic-drift (spontaneous chromosomal) mutations had a unique sensitivity to bile and restricted growth in the presence of a very low concentration of bile salts No. 3 (0.075% (w/v)) but also had the ability to survive in a high concentration (19.2%) of the substance. Following intraperitoneal administration with 10(7) cfu, N-RM25 colonised and survived (10(1)-10(3) cfu/g) in the liver and spleen of mice for over 24..