Salmonellosis is a major health concern in both human and animal medicine, which is caused by infection of the Gram-negative bacteria Salmonella. Controlling Salmonellosis may become more difficult because of the widespread of drug-resistant Salmonella. To provide insight into the development of intervention strategies alternative to antibiotics, we focus on a better understanding of host-Salmonella interactions, with an emphasis on defining the role of its important virulence factor, AB-type exotoxins, in Salmonella pathogenesis. The first Salmonella AB-type exotoxin identified is typhoid toxin. This toxin displays A2B5 stoichiometry, distinct from all other bacterial AB-type toxins discovered thus far (e.g., pertussis, tetanus, cholera, anthrax, shiga and diphtheria toxins). The delivery mechanism of this toxin is also distinct, which involves a two-stage membrane trafficking process: (1) exocytic transport from infected host cells and (2) endocytosis into target host cells. Typhoid toxin is secreted by typhoid fever-causing Salmonella enterica serovar Typhi (Salmonella Typhi or S. Typhi) during infection, which appears to play a significant role in typhoid disease progression and chronic infection. Some of nontyphoidal Salmonella (NTS) also encode typhoid toxin orthologs/ Salmonella A2B5 toxins that appear to have evolved in the context of NTS infection.
Therefore, the main focus of my research program is on the Salmonella A2B5 Toxins: Biology, Pathogenesis, and Neutralization. We use a multidisciplinary approach, a combination of microbiology, immunology, cell biology, biochemistry, structural biology, and glycobiology, to define in molecular, cellular, and organismal level the interactions between host and bacterial pathogens. Our research is anticipated to contribute not only to the development of much-needed innovative controlling strategies against Salmonella infection and its associated diseases, but also to the advancement of our understanding of bacterial AB-type exotoxin biology and function.
Our ongoing research is supported, in part, by National Institutes of Health (RO1 awards AI141514, AI139625, & AI137345), USDA National Institute of Food and Agriculture, and the Mizutani Foundation for Glycoscience.
We are recruiting new members to the dynamic and collegial group!
Please contact PI, Jeongmin Song (js2957 at cornell.edu) with your CV, if you are interested.