Characterization of differentiation antigens expressed in bovine lymphosarcomas

To characterize the cell-surface antigens expressed in tumour cells derived from bovine leukosis and to determine their cell lineages, the immunophenotypes of the tumour cells from 13 bovine lymphosarcomas were examined with 13 monoclonal antibodies (mAbs). Of 13 cattle with lymphosarcomas, four were identified clinically as having the thymic-type sporadic bovine leukosis (SBL) and one as having the skin-type; two had enzootic bovine leukosis (EBL) and six were untypable. Flow cytometric analysis revealed that the tumour cells from nine cases were of T-cell lineage (BoCD5+, BoCD2+ or BoCD2-) and two were of B-cell lineage (MHC-II+, BoCD5+, IgM+); there were two bovine leukaemia virus-infected cattle (EBL). T-cell tumours appeared to originate from immature (BoCD4-, BoCD8-) T cells, but there was no significant relationship between clinical type (EBL, calf-, skin- and thymic-type) and tumour-cell immunophenotype.