A FLOW CYTOMETRIC METHOD FOR IDENTIFYING MAREKS-DISEASE VIRUS PP38 EXPRESSION IN LYMPHOCYTE SUBPOPULATIONS

Identification of Marek's disease virus-infected lymphocytes is essent ial for a full understanding of the pathogenesis of Marek's disease. T his paper describes the development of a simple, quantitative and repr oducible flow cytometric technique for the identification of the pheno type of Marek's disease virus-infected lymphocytes. The method is base d upon the detection of the Marek's disease virus-specific phosphoprot ein pp38, in saponin-permeabilized lymphocytes, using the monoclonal a ntibody BD1, and the identification of the phenotype of pp38(+) lympho cytes using monoclonal antibodies against lymphocyte surface markers. pp38 expression in the spleen was demonstrated in the cytolytic phase of infection. The mean proportion of pp38(+) lymphocytes at 4 days pos t-infection was 0.43%. Of these, 95% were B lymphocytes, while only 4% were T lymphocytes (both CD4(+) and CD8(+)). The potential of the tec hnique for the investigation of the cytolytic phase of Marek's disease is discussed.