JMV Marek's disease tumor cells have B-cell characteristics

In vivo and in vitro methods were used to determine whether JMV Marek's disease (MD) tumor cells have B-cell or T-cell characteristics. JMV tumor cells were treated with anti-T-cell serum (ATS) and complement (C) or anti-B serum (ABS) and C and then inoculated into 1-day-old chickens. Within 2 weeks of inoculation, 95% of chickens inoculated with ATS- and C-treated cells died of JMV-induced leukemia, whereas only 10% of chickens inoculated with ABS- and C-treated cells succumbed. This in vivo result indicated that the malignant cells may be B cells. In vitro studies corroborated this conclusion. ABS and C killed 99 to 100% of cultivated JMV cells, whereas little or no killing of JMV cells was achieved by ATS and C, as demonstrated by trypan blue dye exclusion or by release of 51Cr from labeled JMV cells. Furthermore, after staining of JMV cells with fluorescein-conjugated rabbit anti-chicken immunoglobulin, all cells fluoresced, indicating that JMV cells have surface immunoglobulin. With support of these lines of evidence, we conclude that JMV Marek's disease tumor cells have B-cell characteristics.