PHA reactivity of spontaneous AKR lymphomas: absolute macrophage requirement

The study of patients with T cell lymphoproliferative disorders often demonstrates a reduced response to mitogens. The T cell lymphoma in AKR mice has been considered a classic experimental model of T cell leukaemias. In this paper ten spontaneous lymphomas from AKR mice were characterized individually in vitro for PHA reactivity. After 60 h. of culture, spontaneous 3H-Thymidine uptake by nylon wool purified spleen cells from individual lymphomas oscillated between 4.724 and 81.125 cpm. These nylon wool purified leukemic cells were not responsive to PHA (S.I. less than 2.5). When these cells were cocultured with an adequate macrophage concentration in the presence of PHA, all could be considered responsive to the mitogen (S.I. greater than 2.5). Results indicate that AKR leukemic cells are responsive to PHA in an absolutely macrophage dependent way.