ISPO

Subpopulation shift of Marek's disease virus serotype 1 (MDV) containing the meq genes in the T cell subsets from chicken infected with MDV1

Kyung-Soo Chang, PhD,a Kazuhiko Ohashi, PhD,a Sung-Il Lee, PhD,a Ahmed Ibrahim, PhD,b and Misao Onuma PhDa

aDepartment of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan, bDepartment of poultry disease, Faculty of Veterinary Medicine, South valley University, Egypt. e-mail: monuma@vetmed.hokudai.ac.jp

ABSTRACT: meq gene (1.0 kb) is present in the genome of very virulent strains of Marek's disease virus serotype 1(vvMDV1), and L-meq gene (1.2 kb) is found in other strains of MDV1, such as JM and CVI988/R6. In order to detect the shifts/conversions in the meq genes present in target cells for MDV, we analyzed the meq genes present among T cell subsets from chickens infected with Md5, JM, and CVI988/R6. The meq gene was detected in the T cell subsets from chickens infected with Md5 strain throughout the experimental period. The meq gene was found in greater quantities in the CD4+ T cells compared to CD8+ T cells. The conversion from the meq to L-meq gene in chickens infected with Md5 occurred mainly in the CD8+ T cell subsets. In the case of chickens infected with JM or CVI988/R6 strain, the L-meq gene was detected in the T cell subsets throughout the experimental period. The conversion from L-meq to meq in chickens infected with CVI988/R6 or JM occurred mainly in the CD4+ T cell subset. The meq gene was detected 10 times higher in the CD4+ T cell than CD8+ T cell from chickens infected with Md5 when the quantitative-competitive PCR (QC-PCR) was used. A larger amount of the PCR products corresponding to the L-meq rather than the meq gene was amplified in the CD8+ T cell subset from chickens infected with JM or CVI988/R6 by QC-PCR. In addition, a decrease in the amount of meq gene in the MDV1-infected chickens was seen in the CD8+ T cell subset. Disappearance of the meq genes was faster in the B21 chicken than in the B19 chicken. These results suggest that an increase in the meq gene may be associated with the formation of CD4+ T cell lymphoma. Since the L-meq gene was present in the CD8+ T cell, the L-meq gene may play a role in both clearance of pathogenic MDV and tumor repression in vivo.

For more information, contact kschangs@hanmail.net

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Carcinogenesis.

http://www.cancerprev.org/Journal/Issues/26/101/1010/4294