MAREKS-DISEASE VIRUS ECORI-Q GENE (MEQ) AND A SMALL RNA ANTISENSE TO ICP4 ARE ABUNDANTLY EXPRESSED IN CD4(-DISEASE LYMPHOMAS() CELLS AND CELLS CARRYING A NOVEL LYMPHOID MARKER, AV37, IN MAREKS)

Mature lymphomas produced in Rhode Island Red (RIR) chickens infected with the RB1B strain of Marek's disease virus (MDV) were examined for the presence of viral DNA and RNA and expression of viral antigens. In situ hybridization showed that all tumours examined contained viral D NA in areas of lymphoid infiltration. In 3/5 tumours, there was a corr elation between the number and distribution of cells expressing the Ma rek's disease EcoRI-Q gene (meg) and those that carried the lymphoid c ell marker AV37. Expression of the MDV-specific phosphoprotein pp38 wa s infrequent in lymphomas but abundant in a splenic tumour which also expressed the viral glycoprotein gB. Northern blot analysis of lymphoc yte fractions purified by immunoaffinity showed that CD4(+) and AV37() fractions from lymphomas expressed meg and the small RNA antisense t o ICP4 (SAR). The results are consistent with the notion that transfor med cells are CD4(+) cells, carrying the AV37 marker and expressing me q and SAR.