Discordant gene and surface expression of the T-cell receptor/CD3 complex in adult T-cell leukemia cells

Cell surface expression of the T-cell receptor (TCR)/CD3 complex on the cells from 11 acute type adult T-cell leukemia (ATL) and 4 lymphoma type ATL patients was examined by flow cytometry. Cells from 10 of 11 acute ATL patients were TCR αβ+ and CD3+, and their mean fluorescence intensities were low (TCRαβ, 25.3-84.6; CD3, 22.8-87.8). Cells from two of four lymphoma type ATL did not express this complex, and the other two were CD3+, TCR αβ-. In contrast, the mean fluorescence intensity of the TCR/CD3 complex in cells from a patient with T4 chronic lymphocytic leukemia was not low (TCR αβ, 129.9; CD3, 117.1). mRNA expressions of the TCR α, β, and CD3 γ, δ, ε, and ζ chains were examined by Northern blots. ATL cells from two acute and two lymphoma types expressed amounts of this complex equal to or greater than those expressed by T4 chronic lymphocytic leukemia. CD3 δ and TCR β mRNA in ATL and T4 chronic lymphocytic leukemia cells were equally stable to actinomycin D treatment. The synthesis of CD3 ζ protein by ATL cells was detected by Western blotting assay. On the basis of these findings, we discuss the possible involvement of the TCR/CD3 complex in activation of ATL cells.