Adult T cell leukemia cell lines that originated from primary leukemic clones also had a defect of expression of CD3-T cell receptor complex.

Surface phenotypes and genotypes of six T cell lines established from four patients with adult T cell leukemia (ATL) were compared with those of fresh ATL cells. The surface antigen densities of CD3 and T cell receptor (TCR) complex examined by OKT3 and WT-31 mAbs on fresh ATL cells were low. But three IL-2-dependent cell lines, SKT-2, SKT-5, and ATL-17-2, established from three patients expressed a high density of CD3-TCR complex on their surfaces. On the contrary, three other cell lines (SKT-1A, SKT-1B, and MMT-2), established from two other patients, expressed a low density of CD3-TCR complex. Genotypic analysis of TCR beta chain (T beta) gene and integration sites of the proviral genome of human T cell lymphotropic virus type 1 demonstrated that SKT-1A, SKT-1B, and MMT-2 were derived from the original leukemic clones. These apparent associations between a defect of expression of CD3-TCR complex and identical genotypes of fresh and cultured cells suggest that the defect of expression of CD3-TCR complex may play a key role for development of ATL.