Establishment and cytological characteristics of two in vitro T‐cell lines derived from a child with acute lymphatic leukemia and a man with adult T‐cell leukemia in Japan

Two permanent T‐cell leukemia lines designated KH‐1 and KH‐2 were established from the peripheral blood of a 9‐year‐old boy with acute lymphoblastic leukemia and a 47‐year‐old man with adult T‐cell leukemia (ATL). No T‐cell growth factor was used. KH‐1 cells grew as single cells and KH‐2 cells formed clusters in suspension culture. E‐rosette formation, the absence of immunoglobulin determinants and Epstein‐Barr‐virus‐associated nuclear antigen, and the presence of T‐cell antigens revealed by monoclonal antibodies were characteristics of these cell lines as in other established T‐cell leukemia lines. Chromosome analysis at the beginning revealed mosaic presence of cells with 46, XY, t (8q+; 15q‐) and 46, XY which was later completely replaced by the latter karyotype in KH‐1, and abnormal karyotype, 47, XY, +3, t (8q‐; 10p+) was maintained throughout the period of in vitro passage in KH‐2. The donor patient of KH‐2 formerly lived in the south‐western part of Japan where ATL is considered endemic and numerous type‐C virus particles were detected electron microscopically, in KH‐2 cell pellets.