Enhanced DNA synthesis in isolated calf lymph node lymphocyte cultures.
Calf sub-mandibular lymph node lymphocytes and human peripheral blood lymphocytes were oxidized by NaIO4. In liquid cell cultures, both types of cells were transformed with enhanced DNA synthesis. In mixed lymphocyte cultures, untreated human lymphocytes were transformed by irradiated-oxidized human cells. However, untreated calf lymphocytes were not transformed by irradiated-oxidized calf cells. Either human or calf lymphocytes were isolated from cell-cell interaction in agarose on slides. After 2-3 days of culture, cells were pulsed with tritiated thymidine. Autoradiography indicated greater numbers of cells with active DNA synthesis in NaIO4-oxidized calf cells and in calf cells incubated with Phaseolus vulgaris E-PHA compared to untreated lymphocytes. Similarly treated human cells did not show any increase in the numbers of cells with active DNA synthesis. No enhancement of DNA synthesis was seen in oxidized calf cells which were reduced with NaBH4 or cultured with hydroxyurea. In these restricted in vitro systems, calf cells are 'transformed' independent of cell-cell interaction, while human cells are not.