|
Research Interests:
|
Streptococcus pneumoniae Gene Expression in vivo
(with D. A. Watson, Ph.D.)
Streptococcus pneumoniae is a leading cause of community acquired pneumonia, bacterial meningitis, and otitis media. Our understanding of pneumococcal pathogenesis remains fragmentary. It is generally believed that the identification and characterization of genes whose expression is enhanced on vivo will provide new insights into the mechanisms underlying bacterial pathogenesis and may identify new vaccine or pharmacological targets. We have recently established two in vivo culture models: the murine peritoneal culture (MPC) and a murine bacteremic culture (MBC) model to investigate in vivo gene expression. Using these models, we are assessing the expression of virulence genes/proteins and functional assays for virulence factors/properties. We are also using Differential Display – PCR techniques and a proteomics approach to identify novel in vivo-expressed products. The goal of this work is to document and characterize S. pneumoniae, gene or protein expression differences or differences in virulence properties, which occur during animal infection.
Recombinant Vaccine Development in Salmonella and Mycobacteria
(with A.D.T. Barrett, Ph.D.)
We are investigating novel approaches for vaccine development to a variety of pathogens using gene fusions and attenuated Salmonella and Mycobacterium vaccine strains. Using cloned DNA sequences derived from a Salmonella gene that encodes a surface-encoded polypeptide, we have developed a plasmid vector in which chimeric proteins are exported to the outer membrane by the Salmonella-encoded export signals. Heterologous antigens produced as fusion proteins with epitopes from cholera toxin B subunit and the HIV gp 120 sequences have been demonstrated on the surface of Salmonella. We have also developed mycobacterium plasmid vectors that effectively express recombinant antigens without using antibiotic resistance and include the promoter and partial coding sequence of the 18kDa immunostimulatory protein of Mycobacterium leprae. Studies to explore the immune response to these heterologous surface-expressed antigens and their efficacy as vaccines are currently under investigation.
|
