LARAD INC — Department of Agriculture SBIR Phase I: 8.3

Description

Poultry companies use ELISA to determine if their flocks have been adequately vaccinatedagainst specific poultry pathogens. These assays are a valuable tool in the control of aviandiseases. Herpesvirus of turkeys (HVT) has been used as a vector to create recombinant vaccines(rHVT) that protect against Marek's disease virus (MDV) and other poultry diseases. TheserHVT vaccines are widely used in modern poultry operations yet no ELISA kit has beendeveloped to differentiate between MDV infected and HVT vectored vaccinated birds. Such anELISA would address research priority 3 improving animal health and well-being by allowingproducers to determine if a flock has been successfully vaccinated leading to better diseasemanagement and control. The cross reactivity between HVT and pathogenic (MDV-1) andvaccine strains (MDV-2) presents a challenge. We propose to approach this problem by usingindividual purified protein antigens from HVT. We will target the glycoproteins from HVT sincethese surface proteins have the most sequence diversity between HVT and MDV. Glycoproteingenes will be cloned separately into a vector containing the maltose binding protein (MBP) geneto facilitate purification. The MBP fusion proteins will be expressed in the baculovirus systemand then affinity purified. Purified antigens will be checked for their utility as antigens in theELISA with monospecific HVT antisera. Those that produce sufficient signals with HVTantisera will then be retested using monospecific MDV-1 and MDV-2 antisera. The ideal antigencandidate will be the MBP-glycoprotein that gives a strong signal with only the HVT antisera.