Dr Deepa Paliwal
University of Reading, UK
Progress in a reverse vaccinology approach for bovine TB
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a significant global pathogen causing eonomic loss in livestock and zoonotic TB in man. Several vaccine approaches are in development including reverse vaccinology, which uses an unbiased approach to select potential antigens using the pathogen's entire repertoire of cell surface associated proteins. Open reading frames (ORF) predicted to meet this definition are selected for expression and their relevance as vaccine candidates tested by direct immunization. Adopting this approach, we cloned and expressed over 129 ORFs from the M.bovis genome, some as concatenated proteins, using a mixture of E.coli and insect cell expression technologies. More than 54% of clones showed soluble expression in one or other host and most have allowed rapid purification of the tagged bTB protein from the host cell background. To assess thier use as immunogens, 45 different proteins, grouped as 5x5 mixtures (loosely based on protein type), were used to immunize 5 groups of cattle (n=3) in a standard prime-boost regimen with an oil in water adjuvant. All seroconverted as demonstrated by the binding of immune sera to Purified Protein Derivative Bovine (PPD-B) and individual proteins with titres that broadly reflected the level of the target protein present in the extract. Current assays are in use to measure serum titre on whole BGC and to measure macrophage uptake of serum coated BCG. Our approach seeks to identify key bTB proteins which, when combined in a protein cocktail, may contribute to the protection required for an effective TB vaccine.
Passionate, motivated scientist, working as Postdoctoral Research Associate, with experience and interest in Microbiology, Molecular Biology and Immunology. My academic credentials include double post-graduation in Biotechnology and PhD in Biological Sciences. My PhD at University of Reading explored underlying molecular mechanisms on how bacteria pathogens can kill insect with the aim of utilizing them as effective biocontrol agents. I have employed dual host-pathogen transcriptomic profiling which allows me to analyse large-scale transcriptomic data (RNA-Seq) through use of Galaxy and another tuxedo platorm. Moreover, various statistical tools on Linux & R program help me understand complex data and allow me to interpret and present RNA & DNA sequencing data for publication work. After attaining PhD, I started working as a PDRA at University of Reading. Here, I have gained experience in various protein expression systems, which could be utilised in the formulation of novel recombinant baculoviruses to express target viral antigens in vitro and in situ. This involvement provides an insight into a new era of vaccine design named reverse vaccinology. This design includes antigen prediction to high-throughput purification, screening and selection of the vaccine composition. Besides my own research, I have been involved in supervising undergraduate and Master's students in their project work in a variety of areas including (but not restricted to) bacterial diversity, molecular biology and phage biology. My activities at the University of Reading, coupled with my 4 years research experience in microbiology, molecular biology and biochemistry at the various lab (UK) have taught me a great deal about project management, developing creative ideas, and thinking on my feet when I had to quickly re-arrange a session on the actual day. I am enthusiastic about science, and have developed my science communication skills by giving departmental presentations, and working with schoolchildren during outreach activities.