David J. Pickup, PhD
Emeritus Associate Professor
421 Jones Building
Box 3020 DUMC
Durham, N.C. 27710
Phone: (919) 684-2480
Fax: (919) 684-8735
Viral inhibition of host immune defenses
Many viruses have evolved mechanisms to protect themselves from host immune defenses. Among this group are the orthopoxviruses, whose members include smallpox virus, one of the deadliest of human viruses, and cowpox virus, the virus that Edward Jenner used to begin the eradication of smallpox.
One of the especially interesting features of theses viruses is their ability to interfere with a wide range of innate and adaptive immune responses to infection. For example, we have found that cowpox virus inhibits inflammation by suppressing the actions of cytokines controlling inflammatory processes. Moreover, the virus does this in several ways: by preventing the synthesis of cytokines; by interfering with normal cytokine-receptor interactions; and by inhibiting cytokine-signaling pathways.
Our main research objectives are to identify mechanisms of virus-host interaction leading to the modification or alteration of host functions. Our working model is that such interactions are amongst the most important factors in viral pathogenesis. In addition, knowledge of these virus-host interactions should help in the development of new vaccines and therapies for a variety of conditions associated with infectious diseases, inflammatory diseases, autoimmune diseases, cancers, and organ transplantation.
Development of improved viral vaccines
Several excellent vaccine platforms exist, but among these, vaccinia virus vaccines have unusual potential for targeting multiple different pathogens because of the extraordinary capacity of these vectors to encode multiple foreign proteins. Replication-defective vaccinia vectors are also extremely safe. Currently, we are investigating the potential of these vaccine vectors to develop optimal mucosal immune responses. In addition, we are interested in the potential of these vectors for safe vaccination of pregnant mothers and newborns against both primary infections and mother-to-child transmission of viral infections.
However, this safety comes at a cost. Because only a small amount of antigen can be produced during the single cycle of viral replication, vectors of this type typically require high doses and multiple boosts to induce protective immune responses. We are interested in finding ways to enhance the immunogenicity of these replication-defective vaccine viruses without compromising on safety.