Phenotypic heterogeneity of Moloney leukemia virus-induced T cel lymphomas.

Abstract

Abstract Inoculation of Moloney leukemia virus into neonatal BALB/c mice induces leukemias with distinctly different gross pathologies based on primary involvement of either the thymus or spleen. To determine whether the differences in gross appearance reflected differences in the T cell subpopulations involved, we examined individual lymphomas for the expression of terminal deoxynu-cleotidyl transferase (TdT), which is expressed in the cortisone-sensitive major thymocyte population, or 20-alpha-hydroxysteroid dehydrogenase (20αSDH), which appears to be expressed in the cortisone-resistant, minor population. Consistent with the differences observed in gross appearance, different subpopulations as defined by these markers were observed in different lymphomas. Approximately one-third of the leukemias involved a TdT-positive T cell and invariably these leukemias had thymic, and occasionally, splenic involvement. Another one-third of the lymphomas were characterized by high levels of 20αSDH, low or undetectable levels of TdT, and were primarily splenic lymphomas with only occasionally thymic involvement. The remaining third of the lymphomas had relatively low levels of both enzymes and could not be classified definitively. The heterogeneity of lymphomas seen in vivo was confirmed in vitro by examining a variety of lymphoma cell lines. Both TdT-positive, 20αSDH-negative and TdT-negative, 20αSDH-positive lymphoma cell lines were observed. These results demonstrate that virus-induced lymphomas can involve different subpopulations of T cells and demonstrate the ability of TdT and 20αSDH to define T cell subpopulations.