title: Characterization of extracellular particles released from continuous cell cultures derived from human leukemia.
abstract: Extracellular particles, with a density of 1.18-1.22 g/cm3 in sucrose, were detected in the culture medium of a continuous cell line (JIII) derived from a patient with monocytic leukemia. These particles contained RNA, DNA, and a DNA polymerase. They synthesized DNA with endogenous templates and primers and also used exogenous DNA but not poly(rC) oligo(dG) as a template. Pretreatment with Nonidet P-40 stimulated DNA polymerase activity while treatment with ribonuclease partially inhibited the enzyme activity. Fluorescent antibodies made to the particles stained both JIII and Z-597 cells derived from human leukemias but not other types of human or nonhuman cultured cells tested. The particles do not appear to be oncornaviruses but may be a particulate antigen associated with malignant cells of hemopoietic and lymphoid origin.
mesh_terms: D000912:Antibodies, Neoplasm; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism; D007938:Leukemia / Q000276:immunology / Q000473:pathology*; D007951:Leukemia, Myeloid; D012313:RNA / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D013698:Templates, Genetic
chemical_list: D000912:Antibodies, Neoplasm; D012313:RNA; D004247:DNA; D012260:Ribonucleases