The value of health monitoring of laboratory animals to performance of reliable biomedical research has been well established. Because enzyme- linked immunoassays (ELISAs) provide an efficient format for testing large numbers of animals, serological monitoring for antibodies to viral agents has become an integral part of routine health surveillance. Use of viral specific antigens for serologic assays is absolutely critical to identification of infected animals and the success of health monitoring programs. Currently, diagnostic viral reagents for immunoassays are produced by propagating the virus in mammalian cells and purifying the intact virus to a limited extent. Reagents prepared in this manner suffer from several serious drawbacks, including exposure of laboratory personnel to zoonotic viruses that can cause serious and life-threatening disease, contamination with mammalian cell products that result in false positive reactions, and production of limited amounts of purified viral products. Recently baculovirus expression systems have been developed which are capable of expressing large amounts of cloned, recombinant proteins in insect cells. Expression of viral antigens in baculoviruses overcomes many of the limitations that plague antigens produced by infected mammalian cells. Therefore, the goal of this project is to develop safer, purer, more specific and more cost effective diagnostic reagents for serologic testing using a baculovirus expression system.
The specific aims of this project include the following: 1) cloning of gene sequences coding for viral immunoreactive proteins into baculoviruses, 2) establishment of conditions for optimal expression of cloned, recombinant antigens, and 3) purification of recombinant proteins and evaluation of the sensitivity and specificity of these antigens in ELISAs. First priority will be given to viruses that pose a human health risk and second priority to those viruses that are more difficult to propagate in vitro or cause special problems for definitive diagnostic testing. Availability of these improved diagnostic reagents for health surveillance of laboratory animals is pivotal to continued improvement and definition of animals for research investigations and fills a critical and immediate need in laboratory animal medicine.
