Establishment of a hairy cell leukemia cell line carrying Tac antigen and phagocytic activity with B-cell...

A hairy cell leukemia cell line designated "Hair-M" was established in a suspension culture derived from the peripheral blood of an 86-year-old Japanese male with a diagnosis of hairy cell leukemia. The Hair-M cells were identified as having prominent hair-like cytoplasmic projections by examination with phase-contrast and scanning electron microscopy. These cells displayed ruffled membranes and stublike microvilli similar to those observed on the surfaces of cells in the peripheral blood of the patient. Immunologic and cytochemical studies on the Hair-M cells confirmed derivation from the clone of the patient's leukemia cells. Although the cultured Hair-M cells had definite B-cell characteristics, such as IgG kappa-chains on the surface and in cytoplasm, they also demonstrated Tac antigen, which is usually expressed on activated T-cells, and myelomonocyte antigens determined by OKM-1 and MCS-1 monoclonal antibodies. Other cell surface markers, including E(-), IgGFc(-), IgMFc(-), C3R(+), Ia-like antigen(+), OKT9(+), OKT10(+), and terminal deoxynucleotidyl transferase(-), were detected; no Epstein-Barr virus-determined nuclear antigen was detected. The karyotype of the Hair-M cells was determined to be 46XY with -11, -14, and two marker chromosomes. The Hair-M cells also had phagocytic activity to rabbit anti-human IgG serum-coated polyacrylamide gel particles.