Response of bone marrow to MC29 avian leukosis virus in vitro.

Infection of avian bone marrow with strain MC29 leukosis virus in vitro resulted in infection, elaboration of virus, and growth of characteristic cells. Newly liberated virus with the infectious and neutralization properties of strain MC29 agent and growth of the cells were demonstrable 48 hr and 5-6 days respectively after infection. Studies by light and electron microscopy revealed similarities between the bone marrow cells and the myeloid elements (myelocytes) of myelocytomatosis notable in the relatively low nucleus/cytoplasm ratio; very large nucleolus; and ribosome-rich cytoplasm with a dense gray (protein) matrix and a grainy or "ground glass"