Immunologic characterization of hairy cell leukemias in continuous culture.

The immunobiologic characteristics of three continuous cell lines established from hairy cell leukemia cells were investigated. All three cell lines continued to produce tartrate-resistant acid phosphatase, the enzymatic marker of hairy cells. Two of these cell lines were B lymphoid in nature. They carried Fc and C receptors, had surface and internal immunoglobulin, and did not form spontaneous sheep red blood cell rosettes. Experiments employing biosynthetic radiolabeling of immunoglobulin demonstrated distinctive immunoglobulin kinetics for each of these two hairy cell lines. One cell line remained quite similar to the original hairy cells from which it was derived whereas the other B lymphoid hairy cell line had undergone a switch in the immunoglobulin isotype produced. The third hairy cell leukemia line was shown to be of thymic derivation. These cells formed spontaneous sheep red blood cell rosettes and did not carry Fc or C receptors. The spontaneous sheep red blood cell rosette-forming cells contained tartrate-resistant acid phosphatase. They did not possess surface on internal immunoglobulin and did not synthesize immunoglobulin in vitro. Hairy cell leukemia cells maintained in permanent cell culture retain their immunobiologic properties and offer the opportunity for indepth study of these unusual cells.