Type C RNA Tumor Virus Isolated from Cultured Human Acute Myelogenous Leukemia Cells

Abstract

Previously, type C RNA tumor virus-related components have been described in blood leukocytes from patients with acute myelogenous leukemia. These components, for example, reverse transcriptase, have been shown to be most closely related to those from two oncogenic subhuman primate type C viruses (woolly monkey sarcoma virus and gibbon ape leukemia virus). Now, we report the continuous production of budding type C viruses with the same characteristic reverse transcriptase by three separate culturings of leukocytes from a single bleeding from a patient with acute myelogenous leukemia. These isolations were made possible by the discovery of a source of conditioned media which sustains exponential growth of human myelogenous leukemia cells in liquid suspension culture.

Benzene--attempts to establish a lower exposure standard in the United States. A review.

“…The recently reported isolation of a complete human RNA tumor virus (Type C) associated with acute myelocytic leukemia (18,24,34) raises again the possiJbility that a chemical oarcinogen activates a latent leukemogenic virus in accord with the generalized suggestion of Too-aro and Huebner (49). The demonstration of a relation between exposure to benzene, the appearance of a virus in exposed human 108 beings, and the occurrence of acute leukem ia in these people would strongly support such an hypothesis.…”

Natural antibodies in sera from healthy humans to antigens on surfaces of type C RNA viruses and cells from primates.

“…Very recently, several reports have described the presence of putative type C virus released from blood cells of a patient with acute myelogenous leukemia (AML) (3) as well as from human embryonic diploid cells (4). A common phenomenon observed in these reports is that replication of these viruses was very poor, which suggests that some mechanism in human cells suppresses (3,4,(12)(13)(14) (19,20), only the labeling of the entire viral envelope was scored as a positive reaction in this study. The results were recorded as follows: -, no viruses were labeled; ±, _50% viruses labeled; ++, >50% viruses labeled in direct tests.…”

Natural human antibodies reactive with primate type-C viral antigens.

“…We have therefore used the simian sarcoma-associated helper virus (SSAV) (21) and the M7 strain of baboon endogenous virus (BEV) (22) to survey human sera for specific antibodies. Also included is a virus (HL23V-1) originally isolated from cultured peripheral leukocytes of a patient with acute myelogenous leukemia (23). HL23V-1 was shown to comprise a mixture of two viruses, one closely related to SSAV, the other to BEV (5,24,25).…”