Phenotype of thymic lymphomas in the mouse

The MP2 cell line was established from a murine leukemia virus-induced thymic lymphoma. Half of the cells were consistently L3T4 positive and less than 5% of the cells were Lyt-2 positive. Single cell cloning on the basis of the presence or absence of Lyt-2 allowed the isolation of four clones with stable phenotypes: (1) Lyt-2^-, L3T4^-; (2) Lyt-2⁺; L3T4^-; (3) Lyt-2^-, L3T4⁺; (4) Lyt2⁺, L3T4^-. These data are discussed in relation to tumour cell heterogeneity and to normal T-cell differentiation pathways.