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The investigators plan to develop a S. typhimurium vaccine strain that will exhibit a near wild-type level of invasiveness to visceral tissues during immunization by either coarse spray or orally and then undergo a surface transformation that will lead to the induction of cross protective immunity to block infection and colonization by a diversity of S. enterica subspecies I serotypes.
Most serotypes of Salmonella enterica are relatively innocuous for chickens and almost constitute normal flora. Nevertheless, Salmonella transmission to humans via its presence in or on chicken eggs or on contaminated broiler meat constitutes a major public health problem. Unfortunately, there are over 2,000 Salmonella serovars with differing LPS O-antigen side chain and flagellar antigens, thus making development of an effective vaccine to block colonization of chickens by all Salmonella serotypes a daunting task. However, S. enterica subspecies I strains demonstrate close genetic relatedness and display an identical lipopolysaccharide core with considerable immunological relatedness between a diversity of outer membrane proteins (SOMPs), including iron regulated outermembrane proteins (IROMPs) that are essential for sequestering iron to enable growth and survival of Salmonella in the visceral environment. The investigators plan to develop a S. typhimurium vaccine strain that will exhibit a near wild-type level of invasiveness to visceral tissues during immunization by either coarse spray or orally and then undergo a surface transformation that will lead to the induction of cross protective immunity to block infection and colonization by a diversity of S. enterica subspecies I serotypes. Their objective therefore is to develop a vaccine and immunization protocol that will reduce if not eliminate, Salmonella colonization of chickens and the transmission of Salmonella through the food chain to humans. If successful, this vaccine and its use will reduce Salmonella disease in humans.