Recombinant DNA molecules and herpesviruses as potential immunogens against infectious bursal disease and Marek's disease viruses

Reported in these studies is the potential of utilizing recombinant DNA molecules and herpesvirus as immunogens against Marek's disease and infectious bursal disease, two very important viral diseases in the poultry industry.; The objective of the first study was to determine whether a recombinant plasmid DNA injected intramuscularly into chickens expressed the gene of interest in vivo and could be subsequently detected in primary and secondary lymphoid tissues. Results demonstrated that plasmid DNA injected directly into the pectoral muscle of chickens is transcribed and translated at the injection site and that the injected DNA was promptly distributed to primary and secondary lymphoid tissues.; Several DNA vaccination experiments were performed to determine the protective capability of a plasmid DNA molecule encoding the VP2 capsid protein gene of infectious bursal disease virus (IBDV) injected into chickens in the presence or absence of chicken interleukin 2 (IL-2) plasmid DNA. The results of these experiments indicate that partial protection against IBDV can be achieved by using the VP2 gene of IBDV as a DNA vaccine. Furthermore, the simultaneous injection of chicken IL-2 plasmid DNA significantly increased the protection after challenge with the virulent strain. It was also found that immunological tolerance may have been induced in one of the chicken experiments by vaccination with plasmid DNA.; The first step in the generation of herpesvirus based recombinant vaccines is the construction of recombinant DNA molecules expressing a foreign gene of interest under control of a eukaryotic promoter flanked by non-essential herpesvirus sequences. The LacZ gene of E. coli and the VP2 gene of IBDV were cloned into MDV flanking sequences including the Sorf3, glycoprotein E, and thymidine kinase genes.; Several attempts were made at the creation of a recombinant Marek's disease virus; however, recombinant virus was never isolated. Possible reasons that could account for these negative results include: enough plaques may have not been produced in order to obtain recombinant virus, detection techniques may have misled us away from recombinant plaques, and while the technique of generating recombinant viruses by homologous recombination has been in use for some time, it is very inefficient.