Isolation of HTLV derived from Japanese adult T-cell leukemia patients in human diploid fibroblast strain IMR90 and the biological characters of the infected cells.

HTLV was isolated in the human diploid fibroblast strain IMR90 directly from the leukemic cells of the Japanese ATL-patients. The infection was checked by the presence of virus-specific p24 and proviral DNA. The isolation was successful in three of four patients. The patient whose virus isolation was unsuccessful contained only a defective viral genome in his leukemic cells. The infected cells produced polykaryons when co-cultured with catS + L-cells. Human leukemia HL60 cells formed clusters adherent to the infected IMR90 cells but not to uninfected IMR90 cells. The former phenomenon was blocked by the ATLL patients' serum.