4524B Thomas Hall

Campus Box 7615
North Carolina State University
Raleigh, NC 27695
919.515.2393 (voice)
919.515.7867 (fax)


MB 461
Introduction to Molecular Virology

MB 718
Introductory Virology



Tim Petty


Research Brief

Modified vaccinia Ankara virus (MVA) is a highly attenuated orthopoxvirus that is being evaluated as a replacement for the current smallpox vaccine, as well as for other applications in antiviral prophylaxis and anti-cancer therapy. MVA appears not to infect model animals or humans productively, and displays a highly restricted host range in cell culture. Despite being unable to infect humans, MVA nevertheless gives rise to an appreciable immune response. As a vaccine, it has been shown to have excellent safety characteristics in humans and animals, and to provide adequate protection against virulent poxviruses in animal models. MVA was generated from the wild-type Ankara strain of vaccinia virus (VAC) by 500+ sequential passages in chicken embryo fibroblasts. During the adaptation of MVA to cell culture, its genome accumulated numerous point mutations and deletions relative to wild-type VAC. The sheer number of sequence alterations has rendered comparative genomics approaches largely ineffective for analyzing the genetic determinants of MVA phenotypes. As a result, the location of these genetic determinants, and the mechanisms by which they contribute to the host range, avirulence, and immunogenicity of MVA, are also largely unknown. My lab, in collaboration with research groups at Duke University and elsewhere, is developing new approaches for the genetic analysis of MVA and other poxviruses. The results of these studies are expected to provide important information for the further development of MVA, and related orthopoxviruses, as vaccine vectors for protection against smallpox and for other applications.

Biographical Sketch

Tim Petty was born and raised in Brighton , England . As a boy he was interested in science and technology as far back as he can remember. At aged 18, Tim left home to attend the University of Manchester where he pursued a degree in biochemistry. During the latter stages of his studies he was captivated by the field of molecular genetics. This interest was reinforced by his undergraduate research project on baker's yeast. After graduating from Manchester in the summer 1983, Tim planned to begin postgraduate studies. However, his attempts to get a position in various yeast labs were rebuffed. These circumstances forced an unanticipated change in the direction of Tim's research interests, and led him to the field of plant virology. Initially, when he accepted a position to study for the Ph.D. at Imperial College , University of London , Tim thought he would be developing genetic techniques for the improvement of crop plants. Instead, a plant virus, which was supposed to be simply a tool, became the object of his thesis research and, variously, an alternating source of frustration and elation. Towards the end of 1986, as his Ph.D. was nearing completion, Tim began looking for job opportunities. At this time the best research training in the world was undoubtedly to be found in the Unites States. This, in combination with a boyhood ambition to work overseas, led Tim to join the 'brain-drain' and in 1987 he took a position as a postdoctoral associate at the University of California , Berkeley . There he worked on elucidating the molecular biology of two distinct kinds of plant viruses. After three years of postdoctoral work, Tim's applications for permanent jobs began to bear fruit, and in the summer of 1990 he joined the faculty of North Carolina State University as an assistant professor in the Department of Microbiology. With support from federal and state granting agencies, Tim established his own research program using plant viruses to investigate fundamental aspects of virus' host interactions. Rising through the faculty ranks, Tim was promoted to his current position of full professor in the summer of 2002. Subsequently, he decided to redirect his research program to focus on human and animal viruses. To facilitate this, Tim joined the Department of Molecular Genetics and Microbiology at Duke University Medical Center as a visiting professor in the summer of 2003, and pursued a six month sabbatical during which he conducted research on poxviruses. After his return to N.C. State University in January 2004, Tim continued to lecture and conduct research in virology.