Detection of specific DNA segments of Marek's disease herpes virus in Japanese quail susceptible to atherosclerosis.
Genetically selected lines of Japanese quail, highly susceptible (SUS) and resistant (RES) to atherosclerosis, were used to study the possible involvement of Marek's disease herpes virus (MDV). An EcoRI gene library of MDV cloned in pBR328 was used to prepare the 32P-DNA probe in dot-blot and Southern blot hybridizations to detect the presence of MDV DNA sequence in the aorta, embryo and other tissue specimens. The viral DNA was found present in the aorta of SUS quail and it increased with the severity of the aortic lesion. For the DNA isolated from the atherosclerotic aorta, the endonuclease restriction map is specific but not identical to MDV genome. When screening the embryos of SUS and RES quail, it was found that all the SUS were positive with approximately 10 or more viral genome equivalents or virus copies per cell. The RES embryos were heterogeneous, 41% negative (less than 0.1 copy per cell), 43% intermediate (1-10 copies per cell) and 16% positive (10 or more copies per cell). The vaccination of SUS quail with the herpes virus of turkey vaccine did not prevent the disease. These results indicated that a part of MDV genome or another related herpes virus genome was integrated into the host DNA of SUS quail. The integrated viral gene or genes are believed to be important in atherogenesis, because they are genetically co-selected with the atherosclerosis-susceptibility.