[Kinetics of the propagation of a murine virus (C57Bl mice) in the lymphoid system and bone marrow of rats (study using electron microscopy)].

Either a Slow (SL) or Early (EL) type of leukemia are respectively induced in rats by the RadLV-Rs derived BL/F (SL) and BL/F (EL) viral populations. The kinetics of virus propagation was studied comparatively in the thymus, spleen, lymph nodes and bone marrow of rats infected either with BL/F (EL) or BL/F (SL). During the first days after inoculation with BL/F (SL), the viral population increased rapidly in all tissues, reaching a peak at day 8 to 10, except in the lymph nodes which were almost devoid of viral particles. A very different pattern was shown by the EL leukemia, indicating the importance of the early distribution of viruses amongst the lymphoid tissues in view of the further development of the disease. The large amount of viruses observed inside the megakaryocytes and budding from these cells confirm that they play a role in the leukemogenesis.