Transformation of foetal human leukocytes <i>in vitro</i> by filtrates of a human leukaemic cell line containing herpes‐like virus

Abstract

Abstract Transformation of foetal human leukocytes followed inoculation with a filtrate of cells of the QIMR‐WIL human leukocyte cell line, previously shown to carry a herpes‐like virus. Proliferation of leukocytes was generally noted 24–35 days after inoculation, and resulted in the establishment of cell lines resembling those derived from peripheral leukocytes of patients with leukaemia or infectious mononucleosis. The sex of representative transformed lines confirmed that they were of foetal origin. Transformation occurred with two separate filtrates of QIMR‐WIL cells, with leukocytes from five individual foetuses, and with leukocytes from bone marrow, thymus and spleen. Various control inocula gave negative results, including culture medium and filtrates of Raji and QIMR‐GOR cell lines. Representative transformed lines were found to fix complement with human serum known to react with QIMR‐WIL and QIMR‐GOR cells; but similar serum showed little evidence of reaction by immunofluorescence. The transformed cell lines studied appeared to be essentially diploid, and subterminal constrictions involving Group C chromosomes were noted in a small proportion of cells in 8/9 lines. In preliminary studies, the transforming factor was found to be sensitive to heat and ether, was sedimented at 70,000 × g and retained by a filter of APD 50 mμ; these results are compatible with the herpes‐like virus of the QIMR‐WIL cells being the transforming factor.