Isolation and characterization of a human T cell leukemia virus type II from a hemophilia-A patient with pancytopenia.

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Abstract
Human T cell leukemia virus (HTLV) type I has been isolated from the cultured T cells of several patients with adult T cell leukemia (ATL) and has been etiologically linked to ATL. However, HTLV‐type II has been isolated only once, from the T cells of a patient with a T cell variant of hairy‐cell leukemia. We report here the isolation of HTLV‐II‐related virus from the cultured T cells of a hemophilia‐A patient with pancytopenia. The T cell line (CM) grows in the absence of T cell growth factor. Cord blood T cells were rapidly transformed when co‐cultivated with irradiated CM cells. Heterologous competition radioimmunoassays using purified HTLV‐I p24 showed the expression of HTLV‐IIMO‐related protein in these cells. Electron microscopy of the CM cells showed the presence of intracellular and extracellular type C viral particles. Comparison of the proviral genome in the CM cell line and the prototype HTLV‐IIMO‐containing cell line (MO) by molecular hybridization with probes specific for HTLV‐IIMO indicated that restriction cleavage sites were identical. The fresh peripheral blood leukocytes of the patient contained two complete copies of the proviral genome, despite the lack of HTLV‐II p24 expression. The virus from the cell line CM is designated as HTLV‐IICM to distinguish it from the original HTLV‐IIMO isolate.