A human B-lymphoblastoid cell line constitutively producing Epstein-Barr herpesvirus and JHK retrovirus. 
The human B-lymphoblastoid cell line, designated JHK-3, with pre-B-cell characteristics, chronically produces two viruses, Epstein-Barr virus (EBV) and JHK virus, an apparently novel retrovirus.  The JHK-3 cells are much more productive of extracellular EBV than the high-producer marmoset line B95-8.  The extracellular virus of the JHK-3 EBV strain is relatively fragile, more broadly dispersed in an ultracentrifuged sucrose gradient than the B95-8 EBV and more susceptible to disruption by combined treatment with urea and dithiothreitol.  By restriction fragment length polymorphism analysis, the JHK-3 EBV strain resembles the EBV strain FF-41.  The JHK-3 cells also produce an incompletely characterized, relatively fragile, enveloped, icosahedral RNA virus that contains Mn(++)-dependent reverse transcriptase.  JHK virions measure 85 nm in ultrathin sections, much smaller than other Retroviridae.  The JHK virus exhibits a distinctive morphogenesis, most nearly resembling C-type retroviruses.  The JHK-3 cell line provides a human cell model for investigating virus/virus interactions and their pathogenetic affects on host cells which chronically and simultaneously produce DNA and RNA viruses.