Simultaneous Expression of T‐Cell and Myeloid Cell Phenotypes in Eight Newly Established HTLV‐I‐positive T‐Cell Lines

Eight cell lines were established from patients with adult T‐cell leukemia, and from normal adults, by cocultivation with human T‐cell leukemia virus type I(HTLV‐I)‐producer cell lines in the presence of interleukin‐2. All of these cell lines harbored HTLV‐I and showed T‐cell markers CD2, CD3 and CD4, hut not B‐cell markers. Unexpectedly, all eight cell lines expressed a myeloid marker CD13 and three of the eight lines also expressed another myeloid marker CD33. Dual staining showed the simultaneous expression of CD3 and CD13 on the same cells. Thus, evidence was obtained for the expression of myeloid antigens on HTLV‐I‐harboring T cells.